Schweizerische Stiftung für Tuberkuloseforschung
Fondation Suisse pour la Recherche sur la Tuberculose
Swiss Foundation for Tuberculosis Research

 

Home

Mission

Board

Award

Laureates

Donations

Contact

SwissTBnetwork

Interna

> SwissTB Award

The Swiss TB laureates

1st SwissTB Award, 2002 Maria Olleros

2nd SwissTB Award, 2003 Prof. Dr. Gaby Pfyffer

3rd SwissTB Award, 2004 Dr. Andreas Diacon

4th SwissTB Award, 2005 Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

5th SwissTB Award, 2006 clinical: Dr. Claudia Tueller, research: Dr. Reto Guler

6th SwissTB Award, 2007 Dr. Corinne Loeuillet

7th SwissTB Award, 2008 Nicole Scherr and Dr. Srinivas Honnappa


Swiss TB Award 2008 Nicole Scherr and Dr. Srinivas Honnappa

Nicole Scherr Department of Biochemistry Biozentrum Basel Basel

Our studies on Protein Kinase G were carried out as a collaboration project of the Biozentrum, Basel and the Paul Scherrer Institute in Villigen.

Dr. Srinivas Honnappa Structural Biology group Paul Scherrer Institut Villigen

We describe the crystal structure of protein kinase G, a crucial virulence factor from pathogenic mycobacteria in complex with a highly specific and potent inhibitor.

Protein kinase G is a eukaryotic serine/threonine kinase that is essential for the intracellular survival of pathogenic mycobacteria inside macrophages. Previously, an inhibitor for protein kinase G was defined that induced mycobacterial killing of internalized mycobacteria. Given the relative simple structure of this inhibitor and the high homology of mycobacterial protein kinase G to eukaryotic kinases, the specificity and selectivity of this inhibitor was puzzling. The crystal structure now shows that the ATP binding pocket of protein kinase G is unique, in that it is characterized by a combination of amino acid residues that is not found in any of the > 500 human kinases analyzed; strikingly, it is exactly this stretch of residues that are prominently interacting with the protein kinase G-specific inhibitor. The finding that unique sequences can be defined within the ATP binding pocket of protein kinase G is important for the development of drugs to combat tuberculosis. The development of novel drugs and vaccines to combat mycobacterial diseases such as tuberculosis are at the forefront of research, given the severity of the disease as well as the development of drug resistance against virtually all available clinically used compounds. Furthermore, Protein Kinase G is an attractive drug target in that (1) kinases have recently been shown to be valid drug targets and (2) blocking Protein Kinase G allows the macrophage to carry out its innate anti-mycobacterial activity. To overcome the subversion of the macrophage anti-microbial function is currently one of the roadblocks in the development of effective anti-tuberculosis therapy. Knowledge of the structure presented in our manuscript will be crucial in the design of compounds that may be useful to target the growth of pathogenic mycobacteria within host macrophages by a novel concept, namely by allowing macrophages to carry out their innate anti-mycobacterial activity thereby circumventing the problem of accessibility of drugs to the mycobacteria. We believe that our findings are of high actual interest in the tuberculosis field. As mentioned above, there is a great need for new drugs to combat tuberculosis and our results may significantly contribute to the development of such drugs. In addition, Protein Kinase G as a promising anti-tuberculosis drug target is in the process of being evaluated as a vaccine candidate.

Publication: Structural basis for the specific inhibition of protein kinase G, a virulence factor of Mycobacterium tuberculosis. Nicole Scherr*, Srinivas Honnappa†, Gabriele Kunz*, Philipp Mueller*, Rajesh Jayachandran*, Fritz Winkler†, Jean Pieters*‡, and Michel O. Steinmetz† *Biozentrum, University of Basel, CH-4056 Basel, Switzerland; and †Biomolecular Research, Structural Biology, Paul Scherrer Insititut,
CH-5232 Villigen PSI, Switzerland

PNAS, 104:12151-12156 (2007) download PDF-document

Swiss TB Award 2007 Dr. Corinne Loeuillet

The tubercle bacillus is one of the major scourges afflicting mankind, causing respectively 8 million cases and 2 million deaths yearly. It has evolved to adopt an intracellular lifestyle, by which it is able to survive precisely within the cells ("phagocytes") devoted to kill bacteria. In so doing, it can survive in the host for its lifetime, fending off its immune responses. Thus, one third of the world population is infected by this bacterium.

In the present paper, it is shown not only that the tubercle bacillus can survive within the phagocyte hostile environment, but also that is has acquired the capacity to trigger innate immune reponses, subverting it to make its host cell impervious to acquired immune responses, thus preserving its ecological niche. In other words, the tubercle bacillus steals a weapon from the immune system, turning it against the effectors of acquired immunity as a defense mechanism.

Mycobacterium tuberculosis subverts innate immunity to evade specific effectors.

Corinne Loeuillet,1 Fabio Martinon2, Cynthia Perez1, Miguel Munoz1, Margot Thome2 and
Pascal R. Meylan1, 3
1 Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland,
2 Département de Biochimie, Universite´ de Lausanne, Lausanne, Switzerland and
3Service des Maladies Infectieuses, Centre Hospitalier Universitaire Vaudois,
Lausanne, Switzerland

Abstract: The macrophage is the niche of the intracellular pathogen Mycobacterium tuberculosis. Induction of macrophage apoptosis by CD4+ or CD8+ T cells is accompanied by reduced bacterial counts, potentially defining a host defense mechanism. We have already established that M. tuberculosis-infected primary human macrophages have a reduced susceptibility to Fas ligand (FasL)- induced apoptosis. To study the mechanisms by which M. tuberculosis prevents apoptotic signaling, we have generated a cell culture system based on PMA- and IFN-γ-differentiated THP-1 cells recapitulating the properties of primary macrophages. In these cells, nucleotide-binding oligomerization domain 2 or TLR2 agonists and mycobacterial infection protected macrophages from apoptosis and resulted in NF-κB nuclear translocation associated with up-regulation of the antiapoptotic cellular FLIP. Transduction of a receptor-interacting protein-2 dominant-negative construct showed that nucleotide-binding oligomerization domain 2 is not involved in protection in the mycobacterial infection system. In contrast, both a dominant-negative construct of the MyD88 adaptor and an NF-κB inhibitor abrogated the protection against FasL-mediated apoptosis, showing the implication of TLR2-mediated activation of NF-κB in apoptosis protection in infected macrophages. The apoptosis resistance of infected macrophages might be considered as an immune escape mechanism, whereby M. tuberculosis subverts innate immunity signaling to protect its host cell against FasL+-specific cytotoxic lymphocytes.

J Immunol. 177:6245-6255 (2006) download PDF-document

 

 

Swiss TB Award 2006

amounting Fr. 5'000.- each goes to the first authors of the two following publications:


C. Tueller, P. N. Chhajed, C. Buitrago-Tellez, R. Frei, M. Frey, M. Tamm, Pneumologie Universitätsspital Basel und Barmelwaid Aarau: Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis. Eur Respir J 2005; 26:767-72.

and

Reto Guler, Maria L. Olleros, Dominique Vesin, Roumen Parapanov, Irene Garcia, Department of Pathology and Immunology, Universität Genf:: Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG Infection. Infection and Immunity 2005; 3668-76.

Press release (german).pdf

Dr. Prashant Chhajed and Dr. Reto Guler accept the SwissTB award 2006 at the official ceremony in the congress center Basel from SwissTB president Dr. Otto Brändli and SwissTB vice-president Prof. Laurent Nicod.


SwissTB Laureate 2006 for the best clinical work
Dr. Claudia Tueller

Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis


C. Tueller1, P.N. Chhajed1, C. Buitrago-Tellez2, R. Frei3, M. Frey4 and M. Tamm1

Depts. of 1Pulmonary Medicine, 2Radiology and 3Bacteriology, University Hospital Basel, Basel and 4Respiratory Medicine, Hospital Barmelweid, Barmelweid, Switzerland

ABSTRACT: At present, further investigations are needed in patients with suspected pulmonary tuberculosis (TB) and either negative sputum smear or without sputum. The aim of the present study was to analyse the yield of bronchoalveolar lavage fluid (BALF) smear and PCR in patients with confirmed pulmonary TB. Patients with a positive culture for Mycobacterium tuberculosis complex in sputum or BALF were analysed over 5 yrs.

In total, 90 out of 230 (39%) patients with culture-positive pulmonary TB had a positive sputum smear, and 120 patients underwent bronchoscopy. BALF smear was positive in 56 (47%), BALF PCR in 93 (78%) patients, and BALF smear and/or PCR was positive in 83%. In total, 71 patients who underwent bronchoscopy and had complete clinical records were further analysed. BALF (smear or Mycobacterium tuberculosis complex-PCR) allowed a rapid diagnosis in 10 (59%) out of 17 patients who had a negative sputum smear, and 49 (91%) out of 54 patients without sputum production. Of these 71 patients, 12 (17%) were only culture positive. Rapid diagnosis of pulmonary TB by smear and/or PCR was made in 190 out of 210 patients (90%) in sputum or BALF.

In conclusion, combined use of bronchoalveolar lavage fluid smear and Mycobacterium tuberculosis complex-PCR has a good diagnostic yield in patients with sputum smear-negative tuberculosis or without sputum production.

download PDF-document



SwissTB Laureate 2006 for the best research work
Dr. Reto Guler

Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG infection


Dr. Reto Guler1,2
1Department of Pathology and Immunology, Centre Medical Universitaire, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland, 2Institute of Infectious Disease and Molecular Medicine, Health Science Faculty, University of Cape Town, South Africa.

Excess Tumor Necrosis Factor (TNF) production is one of the main causes of pathogenesis of severe inflammatory diseases such as rheumatoid arthritis. Today, rheumatoid arthritis patients are treated with soluble TNF receptor fusion protein which neutralize excess TNF. However, anti-TNF therapies to treat inflammatory diseases have introduced a new threat since TNF inactivation is associated with the recurrence of tuberculosis and also of many opportunistic infections. Consequently, experimental animal models should provide important understanding of the biological role of the interaction between TNF and its neutralizing soluble TNF receptor fusion protein in serious infections. Therefore, we investigated the interaction between TNF and soluble TNF receptor fusion protein (sTNFR1) in host defense against an avirulent mycobacteria, Mycobacterium bovis BCG. The generation of transgenic mice expressing high levels of human sTNFR1 have allowed to demonstrate that total inhibition of TNF is associated with impaired granuloma formation, reduced macrophage activation, dysregulated cytokine production, deficiency in bactericidal mechanisms, leading to bacterial overgrowth and animal death. However, partial inhibition of TNF by low levels of soluble TNFR resulted in a more rapid activation of innate protective immune response to BCG infection associated with increased macrophage activation, enhanced regulated TNF release, more rapid granuloma differentiation, and increased bactericidal mechanisms. In conclusion, whereas total neutralization of TNF led to increased susceptibility to mycobacterial infection, partial TNF inhibition resulted in enhanced granuloma formation and increased macrophage activation. Therefore, modulation of TNF-associated functions would be more suitable than total TNF inhibition for efficient anti-TNF therapies.

Publication: Guler, R., M. L. Olleros, D. Vesin, R. Parapanov, and I. Garcia. 2005. Differential effects of total and partial neutralization of tumor necrosis factor on cell-mediated immunity to Mycobacterium bovis BCG infection. Infect Immun 73:3668.

download PDF-document

 

SwissTB Award 2005

Dr. Giorgio Ferrari accepts the SwissTB Award 2005 at the official ceremony in the KKL Lucerne from SwissTB president Dr. Otto Brändli.

Dr. Liem Nguyen

Dr. Anne Walburger

Dr. Giorgio Ferrari

Dr. Anil Koul

SwissTB Laureates 2005
CoApplicants: Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

A novel drug target to overcome intrinsic antibiotic resistance of Mycobacterium tuberculosis. Liem Nguyen1, Anne Walburger1, Giorgio Ferrari1, Anil Koul2
1Biozentrum, University of Basel, Basel Switzerland, 2Axxima Pharmaceuticals, Munich, Germany.

Mycobacterium tuberculosis is responsible for the most mortality world wide as a single infectious agent. Chemotherapy of this disease is hampered by the inaccessibility of the mycobacterial cell wall, which renders high resistance of this bacterium to almost available antibiotics. In this proposal for the SwissTB award 2005, we present our discovery of a mycobacterial protein kinase that could be used for the development of novel anti-mycobacterial compounds circumventing the inherent problem of mycobacterial cell wall as a barrier for chemotherapy.

Background
The first barrier a microbial pathogen has to face when infecting multicellular organisms is the innate immune defense system in which a key player is the macrophage. These “professional phagocytes” recognize microbes and engulf them into vacuoles called phagosome. Phagosomes then fuse with lysosomes, resulting in the degradation of the cargo by resident hydrolytic enzymes. In contrast to what happens with other microbes, Mycobacterium tuberculosis can prevent the fusion of their phagosomes with lysosomes, thereby surviving intracellularly. We identified a secreted mycobacterial protein kinase, protein kinase G that plays crucial role for the blockage of phagosome-lysosome fusion. Genetic disruption of this kinase results in immediate transfer of mycobacteria to lysosomes and consequent mycobacterial cell death. A chemical screen for protein kinase G inhibitors led to the discovery of a tetrahydrobenzothiophene, which specifically inhibits the kinase activity of protein kinase G. This compound, as expected, accelerates the phagosome maturation process and mediates enhanced bactericidal activity of macrophages against Mycobacterium tuberculosis.

Significance
Most anti-tuberculous antibiotics used today intend directing intracellular mycobacterial targets to stop Mycobacterium tuberculosis growth. Instead, targeting protein kinase G would allow the macrophage to carry out its innate anti-bacterial activity by shuttling the bacterium to lysosomes. Moreover, by targeting an extracellular functioning molecule like protein kinase G, the problem of chemical transportation through the inaccessible mycobacterial cell wall could be avoided.

References
Walburger A*, Koul A*, Ferrari G*, Nguyen L*, Prescianotto-Baschong C, Huygen K, Klebl B, Thompson C, Bacher G, Pieters J. Protein kinase G from pathogenic mycobacteria promotes survival within macrophages. Science. 2004 Jun 18; 304 (5678):1800-4.
(* Note that these authors contributed equally to the work).

This Abstract as PDF-Document.

Sciene 2004; 304: 1800-1804. download PDF-Document

SwissTB Laureate 2004 Dr. Andreas Diacon

Diagnostic tools in tuberculous pleurisy: A direct comparative study
Diacon AH, van de Wal BW, Wyser C, Smedema JP, Bezuidenhout J, Bolliger CT, Walzl G
Departments of Internal Medicine, Anatomical Pathology, and Medical Biochemistry, Tygerberg Academic Hospital, Stellenbosch University, Cape Town, South Africa


Tuberculous (TB) pleurisy is due to infection of the pleural space with TB bacteria. This causes inflammation and accumulation of fluid around the lung. Patients suffer from dyspnoea, cough, malaise and chest discomfort. This condition is frequent where this study was carried out. It remains difficult to diagnose, however, because both sputum and pleural fluid samples rarely contain TB bacteria and because other diseases can present with quite the same symptoms and signs. Several tests for establishing the diagnosis of TB pleurisy are available to date, of which thoracoscopy is the most accurate yet most expensive. Thoracoscopy is a minor surgical procedure during which all fluid is removed, the pleural cavity is inspected and samples are taken under visual control. Pleural biopsies often produce positive bacterial cultures that can be used for antibiotic resistance testing. More recently, novel and relatively low-cost biochemical tests on pleural fluid have been developed, but not directly compared to thoracoscopy. Adenosine deaminase activity (ADA) in pleural fluid is such a test. Many regions with a high incidence of TB also suffer from limited financial resources and are in need of an affordable diagnostic strategy for pleural effusions of unknown origin. The goal of this study was to define the best test strategy next to thoracoscopy for the diagnosis of TB pleurisy.
For this purpose we prospectively recruited 51 patients with exudative pleural effusions undiagnosed after a comprehensive clinical workup. The final diagnosis was TB in 42 patients (82%), cancer in 5 (10%), and idiopathic in 4 patients (8%). As expected, thoracoscopy was the best test for TB pleurisy with a yield of 100% (positive culture: 76%). The diagnostic sensitivity of bronchial wash and pleural fluid culture were low (both 7%). The traditional closed (blind) needle biopsy had a yield of 79% (positive culture: 48%). ADA alone was 95% sensitive and 89% specific. ADA combined with the pleural fluid lymphocyte count was 89% sensitive and 100% specific, but the rate of positive cultures was only 7%. The overall best alternative test was a combination of ADA, lymphocyte count and closed needle biopsy, which reached 93% sensitivity, 100% specificity, and yielded 52% of positive cultures.
This study allowed us to propose recommendations for the workup of undiagnosed exudative pleural effusions in a high incidence area for TB. For patients with typical clinical presentation, combined pleural fluid ADA level and cellcount is an accurate first step for the diagnosis of TB pleurisy. If this test is negative in a situation of high clinical suspicion of TB pleurisy, if antibiotic resistance is of concern, or if other possible diagnoses are strongly considered, thoracoscopy is the method of choice. If thoracoscopy is not available, closed needle biopsy should be performed and combined with pleural fluid analysis for ADA, lymphocyte count and mycobacterial culture. This alternative provides a high diagnostic yield and can even be performed in outpatient settings. It can replace thoracoscopy at considerably lower expense in areas with high incidence of TB, which is of particular relevance for resource-poor countries.

European Respiratory Journal 2003; 22: 589-591. download PDF-Document

SwissTB Laureate 2003 Prof. Dr. Gaby Pfyffer

Testing of susceptibility of Mycobacterium tuberculosis to pyrazinamide with the nonradiometric BACTEC MGIT 960 system. Pfyffer GE, Palicova F, Rusch-Gerdes S. Swiss National Center for Mycobacteria, Department of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8028 Zurich, Switzerland.

The reliability of the novel BACTEC MGIT 960 pyrazinamide (PZA) kit (Becton Dickinson Microbiology Systems, Sparks, Md.) was assessed for testing of susceptibility of Mycobacterium tuberculosis to PZA. Results generated by the BACTEC MGIT 960 system (Becton Dickinson) were compared with those obtained with the BACTEC 460TB system. Extensive proficiency testing (phase I) and reproducibility testing (phase II) as well as susceptibility testing of blinded strains of M. tuberculosis from the Centers for Disease Control and Prevention (phase III) were performed prior to testing 58 strains isolated from clinical specimens (phase IV). After resolution of discrepant results obtained by the two BACTEC methods by two other laboratories which acted as independent arbiters (phase V), overall agreement of the BACTEC MGIT 960 system with the BACTEC 460TB system for PZA testing of phase IV strains was 96.6%. Between the two systems there was no statistically significant difference in time until results were obtained, i.e., 6.8 days (BACTEC MGIT 960) versus 5.4 days (BACTEC 460TB), the latter not counting the time required for a subculture with a growth index of 200, however. The new BACTEC MGIT PZA susceptibility testing procedure works equally well for inocula prepared from liquid (MGIT) and solid (Lowenstein-Jensen) cultures. PZA MGIT medium in plastic tubes yielded results equivalent to medium dispensed in glass tubes.

J Clin Microbiol. 2002 May;40(5):1670-4. download PDF-Document

download the UniJournal article "Tuberkulose in Baku" (in German)
with kind permission of the publisher

SwissTB Laureate 2002 Maria Olleros

Transmembrane TNF induces an efficient cell-mediated immunity and resistance to Mycobacterium bovis BCG infection in the absence of secreted TNF and LT-a1. Maria L. Olleros*, Reto Guler*, Nadia Corazza† , Dominique Vesin*, Hans-Pietro Eugster‡, Gilles Marchal+, Pierre Chavarot+, Christoph Mueller†, and Irene Garcia2*

*Department of Pathology, University of Geneva ; †Department of Pathology, University of Bern ; ‡Department of Internal Medicine, University Hospital Zurich, Switzerland; and
+Laboratoire du BCG and Unité de Physiopathologie de l’Infection, Institut Pasteur, Paris, France.1This work was supported by Grants 3200-054401.98 and 3200-062026.00 (to I.G.) and 31-53961.98 (to C.M.) from the Swiss National Foundation for Scientific Research and from Roche and Novartis Foundations.

The contribution of a transmembrane (tm) form of tumor necrosis factor (TNF) to protective immunity against Mycobacterium bovis BCG was studied in transgenic mice expressing a noncleavable transmembrane TNF but lacking the TNF-lymphotoxin-a (LT-a) locus (tm TNF tg mice). These mice were as resistant to BCG infection as wild-type mice, whereas TNF/LT-a -/-, TNF-/- and LT-a -/- mice succumbed. Tm TNF tg mice developed granulomas of smaller size but at 2-4 fold increased frequencies compared with wild-type mice. Granulomas were mainly formed by monocytes and activated macrophages expressing tm TNF mRNA and accumulating acid phosphatase. Nitric oxide synthase 2 (NOS2) activation as a key macrophage bactericidal mechanism, was low during the acute phase of infection in tm TNF tg mice, but still sufficient to limit bacterial growth and increased in late infection. IL-12 serum levels of tm TNF tg mice exceeded those of wild-type mice and IL-18 serum concentrations were similar to those of wild-type mice. Infection with virulent Mycobacterium tuberculosis resulted in very rapid death of TNF/LT-a -/- mice but survival of tm TNF tg mice which presented an increase in the number of CFU in spleen (5-fold) and lungs (10-fold) as compared to bacterial load of wild-type mice. In conclusion, the transmembrane form of TNF induces an efficient cell-mediated immunity and total resistance against BCG even in the absence of LT-a and secreted TNF. However, tm TNF mediated protection against virulent M. tuberculosis infection can also be efficient but not as strong as in BCG infection in which cognate cellular interactions may play a more predominant role in providing long-term surveillance and containment of BCG-infected macrophages.

 

J. Immunol.1687:3394-3401 (2002). download publication as PDF-document
 

Welcome to SwissTB -> next award: Award


© 2001-2007 SwissTB, last modification: PI, 21/4/08

Willkommen

Ziele

Stiftungsrat

Preis

Preisträger

Spenden

Kontakt

SwissTBnetwork

Interna

>SwissTB Preis

SwissTB Preisträger

Erster SwissTB Preis, 2002 Maria Olleros

Zweiter SwissTB Preis, 2003 Prof. Dr. Gaby Pfyffer

Dritter SwissTB Preis, 2004 Dr. Andreas Diacon

Vierter SwissTB Preis, 2005 Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

Fünfter SwissTB Preis, 2006 Klinik: Dr. Claudia Tueller, Forschung: Dr. Reto Guler

Sechster SwissTB Preis, 2007 Dr. Corinne Loeuillet

Siebter SwissTB Preis, 2008 Nicole Scherr und Dr. Srinivas Honnappa


Swiss TB Award 2008 Nicole Scherr und Dr. Srinivas Honnappa

Tuberkulose ist weltweit noch immer eine der häufigsten Infektionskrankheiten mit gegen
zwei Millionen Todesfällen jedes Jahr. Anlässlich des Welt-Tuberkulose-Tags vom 24.
März 2008 verleiht die Schweizerische Stiftung für Tuberkuloseforschung Swiss TB bereits
zum siebten Mal den von der Lungenliga Zürich gesponserten Swiss-TB-Award. Mit dem
Preis in der Höhe von Fr. 10‘000 ausgezeichnet werden dieses Jahr die jungen Wissen-
schaftler Nicole Scherr und Dr. Srinivas Honnappa.

Nicole Scherr Department of Biochemistry Biozentrum Basel Basel

Our studies on Protein Kinase G were carried out as a collaboration project of the Biozentrum, Basel and the Paul Scherrer Institute in Villigen.

Dr. Srinivas Honnappa Structural Biology group Paul Scherrer Institut Villigen

Mit dem diesjährigen SwissTBAward, der von der Lungenliga Zürich gesponsert wird, werden die jungen Forscher Nicole Scherr, Doktorandin bei Jean Pieters am Biozentrum der Universität Basel, und Dr. Srinivas Honnappa, Postdoktorant bei Michel Steinmetz am Paul Scherrer Institut in Villigen, ausgezeichnet: Sie haben die Struktur eines Signalmoleküls des Tuberkuloseerregers entschlüsselt und damit der Entwicklung effizienter Medikamente im Kampf gegen die Tuberkulose neue Möglichkeiten eröffnet. Die Auszeichnung bedeutet den beiden Wissenschaftler viel: „Wir fühlen uns durch den SwissTBAward sehr geehrt. Unser Projekt war enorm arbeitsintensiv und risikoreich, wussten wir doch bis zum Schluss nicht, ob es uns überhaupt gelingen würde, die komplexe Struktur des Signalmoleküls PknG zu entschlüsseln“, so Nicole Scherr und Srinivas Honnappa.

Strukturentschlüsselung als Basis Hintergrund ihrer Forschungsarbeit ist eine besondere Eigenschaft des Tuberkulosebakteriums: „Tuberkulosebakterien haben effiziente Strategien entwickelt, um dem menschlichen Immunsystem ein Schnippchen zu schlagen“, erklärt Nicole Scherr. So versuchen die Bakterien gar nicht erst, den menschlichen Fresszellen zu entgehen, sondern lassen sich ohne Gegenwehr verspeisen. Sie werden dabei jedoch nicht etwa unschädlich gemacht: Mit einem speziellen Signalmolekül, der so genannten Proteinkinase G (PknG), die bereits 2004 vom Team um Jean Pieters am Biozentrum Basel entdeckt wurde, verhindert das Tuberkulosebakterium, dass es in der Fresszelle verdaut und damit vernichtet wird. Könnte die PknG nun durch ein Medikament geblockt werden, könnte auch der Selbstschutz des Tuberkulosebakteriums teilweise aufgehoben und damit die Vermehrung des Erregers gehemmt werden, so die Überlegung der Forscher des Basler Biozentrums. Um eine entsprechende Substanz – einen so genannten Inhibitor – zu entwickeln, war jedoch vertieftes Wissen über die Struktur des PknG nötig.

Aufwändige Probenvorbereitung

Um den Aufbau der PknG zu analysieren, arbeitete das Biozentrum Basel mit dem Team von Michel Steinmetz am Paul Scherrer Institut in Villigen zusammen. Srinivas Honnappa bediente sich der Röntgenkristallografie, um die Struktur des Moleküls zu entschlüsseln. Dabei wird im Synchrotron Röntgenstrahlung durch eine kristallisierte Probe geschossen. Die grösste Herausforderung bestand nun darin, die Probe der PknG entsprechend zu präparieren: „Wir mühten uns beinahe zwei Jahre damit ab, die Proben zu reinigen und an schliessend brauchbare Kristalle zu züchten“, so Nicole Scherr. Der Durchbruch gelang erst, als die Nicole Scherr zusammen mit ihrer Kollegin Gabriele Kunz eine frische Probe unverzüglich nach Villigen brachten und Srinivas Honnappa zugleich eine neue Methode, die Kristalle zu gefrieren, einsetzte. Honnappa gelang es schliesslich, das Molekülmodell der PknG sowie einen Inhibitor, der das Funktionieren der PknG stark einschränkt, zu bauen. Die genaue Kenntnis über die Struktur der PknG macht es nun möglich, einen optimalen Inhibitor zu entwickeln, der die PknG gezielt blockt und dabei andere Proteinkinasen im menschlichen Körper nicht oder kaum tangiert“, erläutert Srinivas Honnappa die Wichtigkeit der nun von Swiss TB ausgezeichneten Grundlagenforschung.

Langer Weg bis zum fertigen Medikament

Die Entwicklung eines effizienten Inhibitors könnte dereinst die Grundlage für neue Medikamente zur Behandlung von Tuberkulose darstellen. Bis zur Entwicklung eines Medikamentes ist es jedoch noch ein langer Weg, auf dem weitere Grundlagenforschung nötig sein wird. Nicole Scherr und Srinivas Honnappa werden auf jeden Fall dabei bleiben und sich weiter mit der Struktur der PknG und möglicher Inhibitoren beschäftigen. Dabei soll auch die erfolgreiche Zusammenarbeit zwischen dem Biozentrum Basel und dem Paul Scherrer Institut weitergeführt werden.

Diesen Artikel ©lungenliga-zh.ch als PDF-Dokument herunterladen

Publication: Structural basis for the specific inhibition of protein kinase G, a virulence factor of Mycobacterium tuberculosis. Nicole Scherr*, Srinivas Honnappa†, Gabriele Kunz*, Philipp Mueller*, Rajesh Jayachandran*, Fritz Winkler†, Jean Pieters*‡, and Michel O. Steinmetz† *Biozentrum, University of Basel, CH-4056 Basel, Switzerland; and †Biomolecular Research, Structural Biology, Paul Scherrer Insititut,
CH-5232 Villigen PSI, Switzerland

PNAS, 104:12151-12156 (2007) download PDF-document

 

Swiss TB Award 2007 Dr. Corinne Loeuillet

Die Tuberkulose ist eine der grossen Geisseln der Menschheit. Sie verursacht jedes Jahr 2 Millionen Neuerkrankungen und von allen Infektionskrankheiten am meisten Todesfälle, nämlich 2 Millionen pro Jahr! Das Tuberkulosebakterium hat sich so gut an seinen Wirt, den Menschen, angepasst, dass es über Jahre und Jahrzehnte nach der Ansteckung in den menschlichen Abwehr- oder Fresszellen, den Makrophagen, überleben kann. Deshalb sind heute bis zu einem Drittel der Menschen weltweit mit Tuberkulose infiziert. Die Makrophagen wären dazu da, eindringende Mikroorganismen oder Schadstoffe unschädlich zu machen.

Die prämierte Arbeit zeigt nun, dass die Tuberkulosebakterien nicht nur in den Makrophagen überleben, sondern deren Abwehrmechanismen zu ihren Gunsten zu verändern: Die derart veränderte Immunitätslage der Makrophagen schützt so die „oekologische Nische“ der Tuberkulosebakterien! Sie „stehlen“ quasi einen unserer immunologischen Abwehrmechanismen und können so trotz unserer guten Infektabwehr im menschlichen Körper überleben.

Mycobacterium tuberculosis subverts innate immunity to evade specific effectors

Corinne Loeuillet,1 Fabio Martinon2, Cynthia Perez1, Miguel Munoz1, Margot Thome2 and
Pascal R. Meylan1, 3
1 Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland,
2 Département de Biochimie, Universite´ de Lausanne, Lausanne, Switzerland and
3Service des Maladies Infectieuses, Centre Hospitalier Universitaire Vaudois,
Lausanne, Switzerland

Abstract: The macrophage is the niche of the intracellular pathogen Mycobacterium tuberculosis. Induction of macrophage apoptosis by CD4+ or CD8+ T cells is accompanied by reduced bacterial counts, potentially defining a host defense mechanism. We have already established that M. tuberculosis-infected primary human macrophages have a reduced susceptibility to Fas ligand (FasL)- induced apoptosis. To study the mechanisms by which M. tuberculosis prevents apoptotic signaling, we have generated a cell culture system based on PMA- and IFN-γ-differentiated THP-1 cells recapitulating the properties of primary macrophages. In these cells, nucleotide-binding oligomerization domain 2 or TLR2 agonists and mycobacterial infection protected macrophages from apoptosis and resulted in NF-κB nuclear translocation associated with up-regulation of the antiapoptotic cellular FLIP. Transduction of a receptor-interacting protein-2 dominant-negative construct showed that nucleotide-binding oligomerization domain 2 is not involved in protection in the mycobacterial infection system. In contrast, both a dominant-negative construct of the MyD88 adaptor and an NF-κB inhibitor abrogated the protection against FasL-mediated apoptosis, showing the implication of TLR2-mediated activation of NF-κB in apoptosis protection in infected macrophages. The apoptosis resistance of infected macrophages might be considered as an immune escape mechanism, whereby M. tuberculosis subverts innate immunity signaling to protect its host cell against FasL+-specific cytotoxic lymphocytes.

J Immunol. 177:6245-6255 (2006) download PDF-document

 

 

SwissTB Preis 2006

Im Betrag von von je sFr. 5'000.- an die Erstautoren der beiden folgenden Arbeiten verliehen:

C. Tueller, P. N. Chhajed, C. Buitrago-Tellez, R. Frei, M. Frey, M. Tamm, Pneumologie Universitätsspital Basel und Barmelwaid Aarau: Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis. Eur Respir J 2005; 26:767-72.

und

Reto Guler, Maria L. Olleros, Dominique Vesin, Roumen Parapanov, Irene Garcia, Department of Pathology and Immunology, Universität Genf:: Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG Infection. Infection and Immunity 2005; 3668-76.

Die Preisträger haben Möglichkeiten aufgezeigt, wie die Tuberkulose rascher und sicherer diagnostiziert werden kann und wie sich der Körper gegen eine Infektion mit Mykobacterien wehren kann. Mit der Anwendung von neuen Immun-Modulatoren (Tumor Necrosis Faktor Alpha-Blockern), z. B. in der Behandlung von Rheumatoider Arthritis werden neue Angriffspunkte für Tuberkulose-Medikamente erkennbar. Gleichzeitig muss aber die Gefahr eines Ausbruchs einer latent vorhandenen Tuberkulose-Infektion wieder vermehrt von den klinisch tätigen Ärzten beachtet werden.
Dass auch junge Schweizerinnen und Schweizer an der Tuberkuloseforschung beteiligt sind, ist wegen der leider immer noch zunehmenden globalen Ausbreitung dieser Infektionskrankheit sehr wichtig .
Das Swiss TB Award wird jährlich für die beste Forschungsarbeit auf dem Gebiet der Tuberkulose durch die Schweizerische Stiftung für Tuberkuloseforschung (www.swisstb.org) verliehen.

Press release (german).pdf

Dr. Prashant Chhajed und Dr. Reto Guler nehmen den SwissTB award 2006 an der offiziellen Feier im Kongresszentrum Basel von SwissTB Präsident Dr. Otto Brändli und SwissTB Vizepräsident Prof. Laurent Nicod entgegen.


SwissTB Preisträgerin 2006 für die beste klinische Arbeit
Dr. Claudia Tueller

Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis
C. Tueller1, P.N. Chhajed1, C. Buitrago-Tellez2, R. Frei3, M. Frey4 and M. Tamm1

Depts. of 1Pulmonary Medicine, 2Radiology and 3Bacteriology, University Hospital Basel, Basel and 4Respiratory Medicine, Hospital Barmelweid, Barmelweid, Switzerland

ABSTRACT: At present, further investigations are needed in patients with suspected pulmonary
tuberculosis (TB) and either negative sputum smear or without sputum. The aim of the present
study was to analyse the yield of bronchoalveolar lavage fluid (BALF) smear and PCR in patients
with confirmed pulmonary TB.
Patients with a positive culture for Mycobacterium tuberculosis complex in sputum or BALF
were analysed over 5 yrs.
In total, 90 out of 230 (39%) patients with culture-positive pulmonary TB had a positive sputum
smear, and 120 patients underwent bronchoscopy. BALF smear was positive in 56 (47%), BALF
PCR in 93 (78%) patients, and BALF smear and/or PCR was positive in 83%. In total, 71 patients
who underwent bronchoscopy and had complete clinical records were further analysed. BALF
(smear or Mycobacterium tuberculosis complex-PCR) allowed a rapid diagnosis in 10 (59%) out of
17 patients who had a negative sputum smear, and 49 (91%) out of 54 patients without sputum
production. Of these 71 patients, 12 (17%) were only culture positive. Rapid diagnosis of
pulmonary TB by smear and/or PCR was made in 190 out of 210 patients (90%) in sputum or BALF.
In conclusion, combined use of bronchoalveolar lavage fluid smear and Mycobacterium
tuberculosis complex-PCR has a good diagnostic yield in patients with sputum smear-negative
tuberculosis or without sputum production.

download PDF-document



SwissTB Preisträger 2006 für die beste Forschungsarbeit
Dr. Reto Guler

Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG infection


Dr. Reto Guler1,2
1Department of Pathology and Immunology, Centre Medical Universitaire, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland, 2Institute of Infectious Disease and Molecular Medicine, Health Science Faculty, University of Cape Town, South Africa.

Excess Tumor Necrosis Factor (TNF) production is one of the main causes of pathogenesis of severe inflammatory diseases such as rheumatoid arthritis. Today, rheumatoid arthritis patients are treated with soluble TNF receptor fusion protein which neutralize excess TNF. However, anti-TNF therapies to treat inflammatory diseases have introduced a new threat since TNF inactivation is associated with the recurrence of tuberculosis and also of many opportunistic infections. Consequently, experimental animal models should provide important understanding of the biological role of the interaction between TNF and its neutralizing soluble TNF receptor fusion protein in serious infections. Therefore, we investigated the interaction between TNF and soluble TNF receptor fusion protein (sTNFR1) in host defense against an avirulent mycobacteria, Mycobacterium bovis BCG. The generation of transgenic mice expressing high levels of human sTNFR1 have allowed to demonstrate that total inhibition of TNF is associated with impaired granuloma formation, reduced macrophage activation, dysregulated cytokine production, deficiency in bactericidal mechanisms, leading to bacterial overgrowth and animal death. However, partial inhibition of TNF by low levels of soluble TNFR resulted in a more rapid activation of innate protective immune response to BCG infection associated with increased macrophage activation, enhanced regulated TNF release, more rapid granuloma differentiation, and increased bactericidal mechanisms. In conclusion, whereas total neutralization of TNF led to increased susceptibility to mycobacterial infection, partial TNF inhibition resulted in enhanced granuloma formation and increased macrophage activation. Therefore, modulation of TNF-associated functions would be more suitable than total TNF inhibition for efficient anti-TNF therapies.

Publication: Guler, R., M. L. Olleros, D. Vesin, R. Parapanov, and I. Garcia. 2005. Differential effects of total and partial neutralization of tumor necrosis factor on cell-mediated immunity to Mycobacterium bovis BCG infection. Infect Immun 73:3668.

download PDF-document

 

SwissTB Award 2005

Dr. Giorgio Ferrari nimmt den SwissTB Preis 2005 an der offiziellen Feier im KKL Luzern von SwissTB Präsident Dr. Otto Brändli in Empfang.

Am Welt-Tuberkulosetag 2005 am 24.03.2005 wurde zum vierten Mal der „Swiss TB Award“ im Betrag von Fr. 10'000.-- an die vier Erstautoren der folgenden Arbeit verliehen: Walburger Anne, Koul Anil, Ferrari Giorgio, Nguyen Liem, Prescianotto-Baschong C., Huygen K., Klebl B., Thompson C., Bacher G., Pieters J.:
Protein kinase G from pathogenic mycobacteria promotes survival within macrophages. Science 2004; 304: 1800-4.
Die vier Preisträger haben mit dieser bahnbrechenden Arbeit aus dem Biozentrum der Universität Basel eine Möglichkeit aufgezeigt, wie die Tuberkulose besser behandelt werden könnte. Der „Swiss TB Award“ wird jährlich für die beste Forschungsarbeit auf dem Gebiet der Tuberkulose durch die Schweizerische Stiftung für Tuberkuloseforschung (www.swisstb.org) verliehen.

Dr. Liem Nguyen

Dr. Anne Walburger

Dr. Giorgio Ferrari

Dr. Anil Koul

SwissTB Laureates 2005
CoApplicants: Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

A novel drug target to overcome intrinsic antibiotic resistance of Mycobacterium tuberculosis. Liem Nguyen1, Anne Walburger1, Giorgio Ferrari1, Anil Koul2
1Biozentrum, University of Basel, Basel Switzerland, 2Axxima Pharmaceuticals, Munich, Germany.

Mycobacterium tuberculosis is responsible for the most mortality world wide as a single infectious agent. Chemotherapy of this disease is hampered by the inaccessibility of the mycobacterial cell wall, which renders high resistance of this bacterium to almost available antibiotics. In this proposal for the SwissTB award 2005, we present our discovery of a mycobacterial protein kinase that could be used for the development of novel anti-mycobacterial compounds circumventing the inherent problem of mycobacterial cell wall as a barrier for chemotherapy.

Background
The first barrier a microbial pathogen has to face when infecting multicellular organisms is the innate immune defense system in which a key player is the macrophage. These “professional phagocytes” recognize microbes and engulf them into vacuoles called phagosome. Phagosomes then fuse with lysosomes, resulting in the degradation of the cargo by resident hydrolytic enzymes. In contrast to what happens with other microbes, Mycobacterium tuberculosis can prevent the fusion of their phagosomes with lysosomes, thereby surviving intracellularly. We identified a secreted mycobacterial protein kinase, protein kinase G that plays crucial role for the blockage of phagosome-lysosome fusion. Genetic disruption of this kinase results in immediate transfer of mycobacteria to lysosomes and consequent mycobacterial cell death. A chemical screen for protein kinase G inhibitors led to the discovery of a tetrahydrobenzothiophene, which specifically inhibits the kinase activity of protein kinase G. This compound, as expected, accelerates the phagosome maturation process and mediates enhanced bactericidal activity of macrophages against Mycobacterium tuberculosis.

Significance
Most anti-tuberculous antibiotics used today intend directing intracellular mycobacterial targets to stop Mycobacterium tuberculosis growth. Instead, targeting protein kinase G would allow the macrophage to carry out its innate anti-bacterial activity by shuttling the bacterium to lysosomes. Moreover, by targeting an extracellular functioning molecule like protein kinase G, the problem of chemical transportation through the inaccessible mycobacterial cell wall could be avoided.

References
Walburger A*, Koul A*, Ferrari G*, Nguyen L*, Prescianotto-Baschong C, Huygen K, Klebl B, Thompson C, Bacher G, Pieters J. Protein kinase G from pathogenic mycobacteria promotes survival within macrophages. Science. 2004 Jun 18; 304 (5678):1800-4.
(* Note that these authors contributed equally to the work).
Dieses Abstract als PDF-Document.

Sciene 2004; 304: 1800-1804. download PDF-Document

SwissTB Laureate 2004 Dr. Andreas Diacon

Ein direkter Vergleich verschiedener diagnostischer Methoden für die Diagnose der tuberkulösen Brustfellentzündung
Diacon AH, van de Wal BW, Wyser C, Smedema JP, Bezuidenhout J, Bolliger CT, Walzl G
Institute für Innere Medizin, Anatomische Pathologie und Medizinische Biochemie, Tygerberg Academic Hospital, Universität von Stellenbosch, Kapstadt, Südafrika

Die tuberkulöse Brustfellentzündung entsteht durch Infektion der Brusthöhle mit Tuberkulose-Bakterien. Dadurch entsteht eine Brustfellentzündung und Flüssigkeit (Pleuraerguss) sammelt sich in der Brusthöhle an, was zu Kurzatmigkeit, Husten, Unwohlsein und Brustschmerzen führt. Wo diese Studie durchgeführt wurde ist diese Krankheit häufig. Sie ist schwierig zu diagnostizieren, weil oft weder in der Ergussflüssigkeit noch im ausgehusteten Schleim nachweisbare Tuberkulose-Bakterien vorhanden sind. Zudem haben andere Krankheiten sehr ähnliche Symptome und Anzeichen. Es gibt verschiedene diagnostische Methoden für die tuberkulöse Brustfellentzündung, von denen die Thorakoskopie die beste, aber auch die teuerste ist. Eine Thorakoskopie ist eine Brustfellspiegelung. Dabei wird der angesammelte Erguss entfernt, die Brusthöhle von innen untersucht und Gewebeproben unter Sicht entnommen. Von Gewebeproben können häufig Bakterien gezüchtet und auf antibiotische Resistenz getestet werden. In letzter Zeit wurden relative preisgünstige, neuartige Analysen für die Ergussflüssigkeit entwickelt, die jedoch nie direkt mit der Thorakoskopie verglichen wurden. Eine solche Methode ist die Bestimmung der Aktivität des Enzyms Adenosin-Deaminase (ADA) im Erguss. Da in Regionen wo Tuberkulose häufig vorkommt auch die finanziellen Ressourcen oft knapp sind, ist eine kostengünstige und doch möglichst exakte diagnostische Methode dringend notwendig. Diese Studie hatte das Ziel, die beste alternative Teststrategie zur Thorakoskopie für die Diagnose der tuberkulösen Brustfellentzündung zu definieren.
Zu diesem Zweck wurden 51 Patienten mit Brustfellentzünung in die Studie aufgenommen, bei denen auch nach ausgiebiger Abklärung keine Ursache für den Pleuraerguss gefunden worden war. Die endgültige Diagnose dieser Patienten war Tuberkulose bei 42 Patienten (82%), ein bösartiger Tumor bei 5 (10%) und bei 4 Patienten (8%) blieb die Diagnose unklar. Wie erwartet schnitt die Thorakoskopie am besten ab mit einer Ausbeute für Tuberkulose von 100% (positive Bakterienkultur: 76%). Die Sensitivität von Lungenspülfüssigkeit und Ergussflüssigkeit war tief (beide nur 7%). Die traditionelle geschlossene (blinde) Nadelbiopsie hatte eine Ausbeute von 79% (positive Bakterienkultur: 48%). ADA alleine war 95% sensitiv und 89% spezifisch. ADA zusammen mit der Lymphoytenzahl im Erguss war 89% sensitiv und 100% spezifisch, aber die Rate von positiven Bakterienkulturen war nur 7%. Der beste alternative Test war die Kombination von ADA, Lymphozytenzahl und Nadelbiopsie, die 93% Sensitivität und 100% Spezifität erreichte. Zudem war die Bakterienkultur in 52% positiv.
Diese Studie erlaubte es uns also eine Strategie für die Abklärung von unklaren Brustfellergüssen in einer Region mit häufiger Tuberkulose zu definieren. Für Patienten mit typischer Präsentation für Tuberkulose ist eine Kombination von ADA und Lymphozytenzahl im Pleuraerguss ausreichend. Wenn dieser Test negativ ist und trotzdem Tuberkulose vermutet wird, wenn antibiotische Resistenz möglich ist oder wenn andere Diagnosen als Tuberkulose wahrscheinlich sind, sollte eine Thorakoskopie durchgeführt werden. Ist die Thorakoskopie nicht verfügbar, ist eine geschlossene Nadelbiopsie zusammen mit ADA und Lymphozytenzählung angezeigt. Diese Alternative hat eine hohe diagnostische Ausbeute und kann ambulant durchgeführt werden. Sie kann in Gebieten, wo Tuberkulose häufig ist, die Thorakoskopie mit deutlich geringeren Kosten ersetzen.

European Respiratory Journal 2003; 22: 589-591. Publikation als PDF-Dokument herunterladen


SwissTB Preisträgerin 2003 Prof. Dr. Gaby Pfyffer

Testing of susceptibility of Mycobacterium tuberculosis to pyrazinamide with the nonradiometric BACTEC MGIT 960 system. Pfyffer GE, Palicova F, Rusch-Gerdes S. Swiss National Center for Mycobacteria, Department of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8028 Zurich, Switzerland.

The reliability of the novel BACTEC MGIT 960 pyrazinamide (PZA) kit (Becton Dickinson Microbiology Systems, Sparks, Md.) was assessed for testing of susceptibility of Mycobacterium tuberculosis to PZA. Results generated by the BACTEC MGIT 960 system (Becton Dickinson) were compared with those obtained with the BACTEC 460TB system. Extensive proficiency testing (phase I) and reproducibility testing (phase II) as well as susceptibility testing of blinded strains of M. tuberculosis from the Centers for Disease Control and Prevention (phase III) were performed prior to testing 58 strains isolated from clinical specimens (phase IV). After resolution of discrepant results obtained by the two BACTEC methods by two other laboratories which acted as independent arbiters (phase V), overall agreement of the BACTEC MGIT 960 system with the BACTEC 460TB system for PZA testing of phase IV strains was 96.6%. Between the two systems there was no statistically significant difference in time until results were obtained, i.e., 6.8 days (BACTEC MGIT 960) versus 5.4 days (BACTEC 460TB), the latter not counting the time required for a subculture with a growth index of 200, however. The new BACTEC MGIT PZA susceptibility testing procedure works equally well for inocula prepared from liquid (MGIT) and solid (Lowenstein-Jensen) cultures. PZA MGIT medium in plastic tubes yielded results equivalent to medium dispensed in glass tubes.

J Clin Microbiol. 2002 May;40(5):1670-4. Publikation als PDF-Document herunterladen

Lesen Sie den UniJournal Artikel "Tuberkulose in Baku"
mit freundlicher Genehmigung des Verlags

SwissTB Laureate 2002 Maria Olleros

Wie kann man die schädlichen Auswirkungen des natürlichen Moleküls TNF, welches eine wichtige Rolle in der Immunantwort spielt, vermeiden ohne dabei seine wichtige Schutzwirkung gegen die Tuberkulose zu verlieren ?
Die Gewinnerin des SwissTB Award 2002, Frau Maria-Luisa Olleros widmet sich im Team von Dr. Irène Garcia-Gabay im Departement für Pathologie an der Universität Genf der Tuberkuloseforschung. Sie interessiert sich ganz besonders für die Moleküle, welche unsere Immunzellen aktivieren und es so unserem Organismus ermöglichen, eine Tuberkulose-Infektion einzudämmen. Der Faktor TNF (auf Englisch Tumor Necrosis Factor, weil dieser Faktor auch eine Rolle in der Zerstörung gewisser Krebszellen spielt) ist eines derjenigen Moleküle, welche in der Immunabwehr eine wichtige Rolle spielen, insbesondere gegen Infektionskrankheiten. Leider hat TNF aber im Verlaufe einer Infektion mit Mycobacterium tuberculosis (dem Erreger der Tuberkulose) nicht nur günstige Auswirkungen: im Verlaufe der Krankheit produziert unser Körper nämlich übermässige Mengen von diesem Faktor, welche schädlich wirken und die Heilung ungünstig beeinflussen können.
In ihrer nun preisgekrönten Arbeit zeigt die junge Doktorandin auf, wie man von der Schutzwirkung des TNF profitieren kann, ohne dabei die schädlichen Wirkungen dieses Faktors in Kauf nehmen zu müssen. Der erfolgreiche Ansatz besteht darin, das Molekül so zu verändern, dass es zwar an der Oberfläche der Immunzellen erscheint, nicht aber in der Blutbahn freigesetzt wird. Frau Olleros hat diesen experimentellen Ansatz im Labor von Dr. Garcia-Gabay in Zusammenarbeit mit zwei weiteren Forschungsgruppen, der von Dr. Christoph Müller an der Universität Genf und der von Dr. Gilles Marchal am Institut Pasteur in Paris realisiert. Ihre Arbeit wird demnächst (April 2002) in der angesehenen amerikanischen Fachzeitschrift The Journal of Immunology veröffentlicht werden.

J. Immunol.1687:3394-3401 (2002). Publikation als PDF-Dokument herunterladen

 

Willkommen bei SwissTB -> nächste Seite: Preis

© 2001-2007 SwissTB, letzte Änderung: PI, 4/21/08


Accueil

Mission

Conseil

Prix

Lauréates

Dons

Contact

SwissTBnetwork

interna

> SwissTB Prix

Les Swiss TB lauréates

Premier prix SwissTB, 2002 Maria Olleros

Deuxième prix SwissTB, 2003 Prof. Dr. Gaby Pfyffer

Troisième prixSwissTB, 2004 Dr. Andreas Diacon

Quatrième prix SwissTB, 2005 CoApplicants: Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

Cinqième prix SwissTB, 2006 clinique: Dr. Claudia Tueller, recherche: Dr. Reto Guler

Sixième prix SwissTB, 2007 Dr. Corinne Loeuillet

Septième prix SwissTB, 2008 Nicole Scherr et Dr. Srinivas Honnappa


Swiss TB Award 2008 Nicole Scherr et Dr. Srinivas Honnappa

Nicole Scherr Department of Biochemistry Biozentrum Basel Basel

Our studies on Protein Kinase G were carried out as a collaboration project of the Biozentrum, Basel and the Paul Scherrer Institute in Villigen.

Dr. Srinivas Honnappa Structural Biology group Paul Scherrer Institut Villigen

We describe the crystal structure of protein kinase G, a crucial virulence factor from pathogenic mycobacteria in complex with a highly specific and potent inhibitor.

Protein kinase G is a eukaryotic serine/threonine kinase that is essential for the intracellular survival of pathogenic mycobacteria inside macrophages. Previously, an inhibitor for protein kinase G was defined that induced mycobacterial killing of internalized mycobacteria. Given the relative simple structure of this inhibitor and the high homology of mycobacterial protein kinase G to eukaryotic kinases, the specificity and selectivity of this inhibitor was puzzling. The crystal structure now shows that the ATP binding pocket of protein kinase G is unique, in that it is characterized by a combination of amino acid residues that is not found in any of the > 500 human kinases analyzed; strikingly, it is exactly this stretch of residues that are prominently interacting with the protein kinase G-specific inhibitor. The finding that unique sequences can be defined within the ATP binding pocket of protein kinase G is important for the development of drugs to combat tuberculosis. The development of novel drugs and vaccines to combat mycobacterial diseases such as tuberculosis are at the forefront of research, given the severity of the disease as well as the development of drug resistance against virtually all available clinically used compounds. Furthermore, Protein Kinase G is an attractive drug target in that (1) kinases have recently been shown to be valid drug targets and (2) blocking Protein Kinase G allows the macrophage to carry out its innate anti-mycobacterial activity. To overcome the subversion of the macrophage anti-microbial function is currently one of the roadblocks in the development of effective anti-tuberculosis therapy. Knowledge of the structure presented in our manuscript will be crucial in the design of compounds that may be useful to target the growth of pathogenic mycobacteria within host macrophages by a novel concept, namely by allowing macrophages to carry out their innate anti-mycobacterial activity thereby circumventing the problem of accessibility of drugs to the mycobacteria. We believe that our findings are of high actual interest in the tuberculosis field. As mentioned above, there is a great need for new drugs to combat tuberculosis and our results may significantly contribute to the development of such drugs. In addition, Protein Kinase G as a promising anti-tuberculosis drug target is in the process of being evaluated as a vaccine candidate.

Publication: Structural basis for the specific inhibition of protein kinase G, a virulence factor of Mycobacterium tuberculosis. Nicole Scherr*, Srinivas Honnappa†, Gabriele Kunz*, Philipp Mueller*, Rajesh Jayachandran*, Fritz Winkler†, Jean Pieters*‡, and Michel O. Steinmetz† *Biozentrum, University of Basel, CH-4056 Basel, Switzerland; and †Biomolecular Research, Structural Biology, Paul Scherrer Insititut,
CH-5232 Villigen PSI, Switzerland

PNAS 104:12151-12156 (2007) download PDF-document

 

Swiss TB Award 2007 Dr. Corinne Loeuillet

Le bacille tuberculeux est un des fléaux majeurs de l'humanité, causant respectivement près de 8 millions de cas et 2 millions de décès annuellement. C'est est un agent qui s'est adapté à son hôte jusqu'à prospérer précisément à l'intérieur des cellules ("phagocytes") qui sont censées tuer les bactéries, lui permettant de persister la vie durant chez l'hôte infecté en déjouant ses réponses immunes. Pas moins de 1/3 de la population mondiale est ainsi infectée.

Dans ce travail, on montre que non seulement le bacille peut survivre dans ce milieu hostile, mais encore qu'il est capable d'utiliser à son avantage la réponse immunitaire innée qu'il déclenche, afin de rendre sa cellule hôte résistante aux réponses immunitaires acquises, ménageant ainsi sa niche écologique. De manière imagée, on peut dire qu'il vole au système immunitaire une arme qu'il retourne pour mieux se défendre contre les réponses immunes acquises.

Mycobacterium tuberculosis subverts innate immunity to evade specific effectors

Corinne Loeuillet,1 Fabio Martinon2, Cynthia Perez1, Miguel Munoz1, Margot Thome2 and
Pascal R. Meylan1, 3
1 Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland,
2 Département de Biochimie, Universite´ de Lausanne, Lausanne, Switzerland and
3Service des Maladies Infectieuses, Centre Hospitalier Universitaire Vaudois,
Lausanne, Switzerland

Abstract: The macrophage is the niche of the intracellular pathogen Mycobacterium tuberculosis. Induction of macrophage apoptosis by CD4+ or CD8+ T cells is accompanied by reduced bacterial counts, potentially defining a host defense mechanism. We have already established that M. tuberculosis-infected primary human macrophages have a reduced susceptibility to Fas ligand (FasL)- induced apoptosis. To study the mechanisms by which M. tuberculosis prevents apoptotic signaling, we have generated a cell culture system based on PMA- and IFN-γ-differentiated THP-1 cells recapitulating the properties of primary macrophages. In these cells, nucleotide-binding oligomerization domain 2 or TLR2 agonists and mycobacterial infection protected macrophages from apoptosis and resulted in NF-κB nuclear translocation associated with up-regulation of the antiapoptotic cellular FLIP. Transduction of a receptor-interacting protein-2 dominant-negative construct showed that nucleotide-binding oligomerization domain 2 is not involved in protection in the mycobacterial infection system. In contrast, both a dominant-negative construct of the MyD88 adaptor and an NF-κB inhibitor abrogated the protection against FasL-mediated apoptosis, showing the implication of TLR2-mediated activation of NF-κB in apoptosis protection in infected macrophages. The apoptosis resistance of infected macrophages might be considered as an immune escape mechanism, whereby M. tuberculosis subverts innate immunity signaling to protect its host cell against FasL+-specific cytotoxic lymphocytes.

J Immunol. 177:6245-6255 (2006) download PDF-document

 

 

Swiss TB Award 2006

amounting Fr. 5'000.- each goes to the first authors of the two following publications:


C. Tueller, P. N. Chhajed, C. Buitrago-Tellez, R. Frei, M. Frey, M. Tamm, Pneumologie Universitätsspital Basel und Barmelwaid Aarau: Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis. Eur Respir J 2005; 26:767-72.

and

Reto Guler, Maria L. Olleros, Dominique Vesin, Roumen Parapanov, Irene Garcia, Department of Pathology and Immunology, Universität Genf:: Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG Infection. Infection and Immunity 2005; 3668-76.

Press release (allemand).pdf

Dr. Prashant Chhajed et Dr. Reto Guler acceptent le prix SwissTB 2006 à l'occasionde la cérémoie officielle au centre de congrès Bâle du président de la SwissTB Dr. Otto Brändli et du viceprésident de la SwissTB Prof. Laurent Nicod.


SwissTB Laureate 2006 for the best clinical work
Dr. Claudia Tueller

Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis
C. Tueller1, P.N. Chhajed1, C. Buitrago-Tellez2, R. Frei3, M. Frey4 and M. Tamm1

Depts. of 1Pulmonary Medicine, 2Radiology and 3Bacteriology, University Hospital Basel, Basel and 4Respiratory Medicine, Hospital Barmelweid, Barmelweid, Switzerland

ABSTRACT: At present, further investigations are needed in patients with suspected pulmonary
tuberculosis (TB) and either negative sputum smear or without sputum. The aim of the present
study was to analyse the yield of bronchoalveolar lavage fluid (BALF) smear and PCR in patients
with confirmed pulmonary TB.
Patients with a positive culture for Mycobacterium tuberculosis complex in sputum or BALF
were analysed over 5 yrs.
In total, 90 out of 230 (39%) patients with culture-positive pulmonary TB had a positive sputum
smear, and 120 patients underwent bronchoscopy. BALF smear was positive in 56 (47%), BALF
PCR in 93 (78%) patients, and BALF smear and/or PCR was positive in 83%. In total, 71 patients
who underwent bronchoscopy and had complete clinical records were further analysed. BALF
(smear or Mycobacterium tuberculosis complex-PCR) allowed a rapid diagnosis in 10 (59%) out of
17 patients who had a negative sputum smear, and 49 (91%) out of 54 patients without sputum
production. Of these 71 patients, 12 (17%) were only culture positive. Rapid diagnosis of
pulmonary TB by smear and/or PCR was made in 190 out of 210 patients (90%) in sputum or BALF.
In conclusion, combined use of bronchoalveolar lavage fluid smear and Mycobacterium
tuberculosis complex-PCR has a good diagnostic yield in patients with sputum smear-negative
tuberculosis or without sputum production.

download PDF-document



SwissTB Laureate 2006 for the best research work
Dr. Reto Guler

Differential Effects of Total and Partial Neutralization of Tumor Necrosis Factor on Cell-Mediated Immunity to Mycobacterium bovis BCG infection


Dr. Reto Guler1,2
1Department of Pathology and Immunology, Centre Medical Universitaire, 1 rue Michel-Servet, 1211 Geneva 4, Switzerland, 2Institute of Infectious Disease and Molecular Medicine, Health Science Faculty, University of Cape Town, South Africa.

Excess Tumor Necrosis Factor (TNF) production is one of the main causes of pathogenesis of severe inflammatory diseases such as rheumatoid arthritis. Today, rheumatoid arthritis patients are treated with soluble TNF receptor fusion protein which neutralize excess TNF. However, anti-TNF therapies to treat inflammatory diseases have introduced a new threat since TNF inactivation is associated with the recurrence of tuberculosis and also of many opportunistic infections. Consequently, experimental animal models should provide important understanding of the biological role of the interaction between TNF and its neutralizing soluble TNF receptor fusion protein in serious infections. Therefore, we investigated the interaction between TNF and soluble TNF receptor fusion protein (sTNFR1) in host defense against an avirulent mycobacteria, Mycobacterium bovis BCG. The generation of transgenic mice expressing high levels of human sTNFR1 have allowed to demonstrate that total inhibition of TNF is associated with impaired granuloma formation, reduced macrophage activation, dysregulated cytokine production, deficiency in bactericidal mechanisms, leading to bacterial overgrowth and animal death. However, partial inhibition of TNF by low levels of soluble TNFR resulted in a more rapid activation of innate protective immune response to BCG infection associated with increased macrophage activation, enhanced regulated TNF release, more rapid granuloma differentiation, and increased bactericidal mechanisms. In conclusion, whereas total neutralization of TNF led to increased susceptibility to mycobacterial infection, partial TNF inhibition resulted in enhanced granuloma formation and increased macrophage activation. Therefore, modulation of TNF-associated functions would be more suitable than total TNF inhibition for efficient anti-TNF therapies.

Publication: Guler, R., M. L. Olleros, D. Vesin, R. Parapanov, and I. Garcia. 2005. Differential effects of total and partial neutralization of tumor necrosis factor on cell-mediated immunity to Mycobacterium bovis BCG infection. Infect Immun 73:3668.

download PDF-document

 

SwissTB Award 2005

Dr. Giorgio Ferrari accepts the SwissTB Award 2005 at the official ceremony in the KKL Lucerne from SwissTB president Dr. Otto Brändli.

Dr. Liem Nguyen

Dr. Anne Walburger

Dr. Giorgio Ferrari

Dr. Anil Koul

SwissTB Laureates 2005
CoApplicants: Drs. Liem Nguyen, Anne Walburger, Giorgio Ferrari, Anil Koul

A novel drug target to overcome intrinsic antibiotic resistance of Mycobacterium tuberculosis. Liem Nguyen1, Anne Walburger1, Giorgio Ferrari1, Anil Koul2
1Biozentrum, University of Basel, Basel Switzerland, 2Axxima Pharmaceuticals, Munich, Germany.

Mycobacterium tuberculosis is responsible for the most mortality world wide as a single infectious agent. Chemotherapy of this disease is hampered by the inaccessibility of the mycobacterial cell wall, which renders high resistance of this bacterium to almost available antibiotics. In this proposal for the SwissTB award 2005, we present our discovery of a mycobacterial protein kinase that could be used for the development of novel anti-mycobacterial compounds circumventing the inherent problem of mycobacterial cell wall as a barrier for chemotherapy.

Background
The first barrier a microbial pathogen has to face when infecting multicellular organisms is the innate immune defense system in which a key player is the macrophage. These “professional phagocytes” recognize microbes and engulf them into vacuoles called phagosome. Phagosomes then fuse with lysosomes, resulting in the degradation of the cargo by resident hydrolytic enzymes. In contrast to what happens with other microbes, Mycobacterium tuberculosis can prevent the fusion of their phagosomes with lysosomes, thereby surviving intracellularly. We identified a secreted mycobacterial protein kinase, protein kinase G that plays crucial role for the blockage of phagosome-lysosome fusion. Genetic disruption of this kinase results in immediate transfer of mycobacteria to lysosomes and consequent mycobacterial cell death. A chemical screen for protein kinase G inhibitors led to the discovery of a tetrahydrobenzothiophene, which specifically inhibits the kinase activity of protein kinase G. This compound, as expected, accelerates the phagosome maturation process and mediates enhanced bactericidal activity of macrophages against Mycobacterium tuberculosis.

Significance
Most anti-tuberculous antibiotics used today intend directing intracellular mycobacterial targets to stop Mycobacterium tuberculosis growth. Instead, targeting protein kinase G would allow the macrophage to carry out its innate anti-bacterial activity by shuttling the bacterium to lysosomes. Moreover, by targeting an extracellular functioning molecule like protein kinase G, the problem of chemical transportation through the inaccessible mycobacterial cell wall could be avoided.

References
Walburger A*, Koul A*, Ferrari G*, Nguyen L*, Prescianotto-Baschong C, Huygen K, Klebl B, Thompson C, Bacher G, Pieters J. Protein kinase G from pathogenic mycobacteria promotes survival within macrophages. Science. 2004 Jun 18; 304 (5678):1800-4.
(* Note that these authors contributed equally to the work).
This Article as PDF-Document.

Sciene 2004; 304: 1800-1804. download PDF-Document

SwissTB Laureate 2004 Dr. Andreas Diacon

Diagnostic tools in tuberculous pleurisy: A direct comparative study
Diacon AH, van de Wal BW, Wyser C, Smedema JP, Bezuidenhout J, Bolliger CT, Walzl G
Departments of Internal Medicine, Anatomical Pathology, and Medical Biochemistry, Tygerberg Academic Hospital, Stellenbosch University, Cape Town, South Africa


Tuberculous (TB) pleurisy is due to infection of the pleural space with TB bacteria. This causes inflammation and accumulation of fluid around the lung. Patients suffer from dyspnoea, cough, malaise and chest discomfort. This condition is frequent where this study was carried out. It remains difficult to diagnose, however, because both sputum and pleural fluid samples rarely contain TB bacteria and because other diseases can present with quite the same symptoms and signs. Several tests for establishing the diagnosis of TB pleurisy are available to date, of which thoracoscopy is the most accurate yet most expensive. Thoracoscopy is a minor surgical procedure during which all fluid is removed, the pleural cavity is inspected and samples are taken under visual control. Pleural biopsies often produce positive bacterial cultures that can be used for antibiotic resistance testing. More recently, novel and relatively low-cost biochemical tests on pleural fluid have been developed, but not directly compared to thoracoscopy. Adenosine deaminase activity (ADA) in pleural fluid is such a test. Many regions with a high incidence of TB also suffer from limited financial resources and are in need of an affordable diagnostic strategy for pleural effusions of unknown origin. The goal of this study was to define the best test strategy next to thoracoscopy for the diagnosis of TB pleurisy.
For this purpose we prospectively recruited 51 patients with exudative pleural effusions undiagnosed after a comprehensive clinical workup. The final diagnosis was TB in 42 patients (82%), cancer in 5 (10%), and idiopathic in 4 patients (8%). As expected, thoracoscopy was the best test for TB pleurisy with a yield of 100% (positive culture: 76%). The diagnostic sensitivity of bronchial wash and pleural fluid culture were low (both 7%). The traditional closed (blind) needle biopsy had a yield of 79% (positive culture: 48%). ADA alone was 95% sensitive and 89% specific. ADA combined with the pleural fluid lymphocyte count was 89% sensitive and 100% specific, but the rate of positive cultures was only 7%. The overall best alternative test was a combination of ADA, lymphocyte count and closed needle biopsy, which reached 93% sensitivity, 100% specificity, and yielded 52% of positive cultures.
This study allowed us to propose recommendations for the workup of undiagnosed exudative pleural effusions in a high incidence area for TB. For patients with typical clinical presentation, combined pleural fluid ADA level and cellcount is an accurate first step for the diagnosis of TB pleurisy. If this test is negative in a situation of high clinical suspicion of TB pleurisy, if antibiotic resistance is of concern, or if other possible diagnoses are strongly considered, thoracoscopy is the method of choice. If thoracoscopy is not available, closed needle biopsy should be performed and combined with pleural fluid analysis for ADA, lymphocyte count and mycobacterial culture. This alternative provides a high diagnostic yield and can even be performed in outpatient settings. It can replace thoracoscopy at considerably lower expense in areas with high incidence of TB, which is of particular relevance for resource-poor countries.

European Respiratory Journal 2003; 22: 589-591. download PDF-Document

SwissTB Laureate 2003 Prof. Dr. Gaby Pfyffer

Testing of susceptibility of Mycobacterium tuberculosis to pyrazinamide with the nonradiometric BACTEC MGIT 960 system. Pfyffer GE, Palicova F, Rusch-Gerdes S. Swiss National Center for Mycobacteria, Department of Medical Microbiology, University of Zurich, Gloriastrasse 30, 8028 Zurich, Switzerland.

The reliability of the novel BACTEC MGIT 960 pyrazinamide (PZA) kit (Becton Dickinson Microbiology Systems, Sparks, Md.) was assessed for testing of susceptibility of Mycobacterium tuberculosis to PZA. Results generated by the BACTEC MGIT 960 system (Becton Dickinson) were compared with those obtained with the BACTEC 460TB system. Extensive proficiency testing (phase I) and reproducibility testing (phase II) as well as susceptibility testing of blinded strains of M. tuberculosis from the Centers for Disease Control and Prevention (phase III) were performed prior to testing 58 strains isolated from clinical specimens (phase IV). After resolution of discrepant results obtained by the two BACTEC methods by two other laboratories which acted as independent arbiters (phase V), overall agreement of the BACTEC MGIT 960 system with the BACTEC 460TB system for PZA testing of phase IV strains was 96.6%. Between the two systems there was no statistically significant difference in time until results were obtained, i.e., 6.8 days (BACTEC MGIT 960) versus 5.4 days (BACTEC 460TB), the latter not counting the time required for a subculture with a growth index of 200, however. The new BACTEC MGIT PZA susceptibility testing procedure works equally well for inocula prepared from liquid (MGIT) and solid (Lowenstein-Jensen) cultures. PZA MGIT medium in plastic tubes yielded results equivalent to medium dispensed in glass tubes.

J Clin Microbiol. 2002 May;40(5):1670-4. download PDF-Document

download the UniJournal article "Tuberkulose in Baku" (in German)
with kind permission of the publisher

SwissTB Laureate 2002 Maria Olleros

Comment éviter la toxicité d’une molécule naturelle et nécessaire pour nos défenses immunitaires, le facteur TNF, tout en bénéficiant de sa puissante activité pour combattre la tuberculose ?
La lauréate, Mme Maria-Luisa Olleros, s’est inscrite dans la lutte contre la tuberculose au sein de l’équipe dirigée par le Dr Irène Garcia-Gabay au Département de Pathologie à l’Université de Genève. Elle s’intéresse particulièrement aux molécules qui activent nos cellules immunitaires et qui rendent possible que notre organisme se défendre contre cette maladie. Parmi les molécules nécessaires à notre défense, une protéine produite naturellement et essentielle pour combattre les infections, est le facteur TNF (de l’anglais Tumor Necrosis Factor, parce que ce facteur joue aussi un rôle dans la destruction de certaines cellules cancéreuses). Cependant, quand l’agent pathogène qui induit la tuberculose, Mycobacterium tuberculosis, envahi nos organes, notre corps produit du TNF en quantité excessive devenant ainsi toxique et néfaste pour notre guérison.
Dans son travail récompensé, Mme Olleros démontre une stratégie pour bénéficier de l’activité toujours nécessaire du TNF en évitant sa toxicité. Cette stratégie consiste à modifier la molécule qu’elle soit exprimée sur la surface des cellules immunitaires mais pas relâchée dans la circulation sanguine. La jeune doctorante a réalisé ce travail dans le laboratoire du Dr Garcia-Gabay en collaboration avec deux autres groupes de chercheurs, le Dr Christoph Müller à l’Institut de Pathologie à l’Université de Berne et le Dr Gilles Marchal à l’Institut Pasteur à Paris en utilisant cette approche expérimentale. Son travail sera publié par la revue scientifique renommée américaine The Journal of Immunology au mois d’avril 2002.

J. Immunol.1687:3394-3401 (2002). PDF-document

 

Bienvenue à SwissTB -> page suivante: Prix

© 2001-2007 SwissTB, dernière modification, PI, 21/4/08