IMMUNOPATHOLOGY OF THE <I>Trypanosoma cruzi</I> INFECTIOUS PROCESS

The Team of Immunopathology of the Trypanosoma cruziInfectious Process is centered on understanding the host-parasite relationship defined by the interaction between host lymphocytes and the parasite Trypanosoma cruzi. More precisely, we study how parasite infection leads to lymphocyte activation and what are the immunopathological consequences of such an activation.

There is a pronounced dysregulation of the immune system during T. cruzi infections in humans and in experimental mouse models. This manifests itself as an initial hypergammaglobulinemia and immunosuppression followed by auto-immunopathology associated with the chronic phases of the disease. Although natural killer cells and parasite-derived suppressive substances have been evoked to explain the immunosuppression, we favoured the hypothesis that this is due to a parasite-provoked intense non specific polyclonal activation of host lymphocytes during the early phases of acute infection. Our studies in infected mice have shown that amongst the activated lymphocyte populations, there is a marked expansion of CD5-positive B-cells (B1) and double negative gamma/delta-T cells. Support for a crucial role for CD5+ B cells came from our studies in xid mice. These mutant mice are deficient in CD5+ B cells and are resistant to T. cruzi associated immunopathology. Our studies allowed us to propose that the amplification in the B-cell and T- cell populations observed after infection is mainly triggered by mechanisms independent of BCR- and TCR- specificities and thus by the secretion of parasite-derived mitogenic and superantigenic activities.

We had identified parasite molecules involved in B cell proliferation and activation. One of these parasite molecules is a proline-racemase, whose gene is the first eukaryotic proline racemase gene described so far. Interestingly, the ability of proline racemase to activate B cells is dependent on exposed epitopes in the active ligand-free enzyme. However, the mechanism of lymphocyte activation remains obscure. We pursued the molecular, biochemical and functional analyses of the parasite proline racemase (TcPRAC) and defined a protein signature capable of identify putative proline racemases of several microorganisms of medical and agricultural importance. Furthermore, we had shown that parasite proline racemase is essential since TcPRAC mutant parasites where TcPRAC gene was 'knocked down' are not viable. Conversely, parasites over expressing TcPRAC genes present an increased differentiation into infective forms and are more virulent to host cells. We are now using new molecular strategies to study the role of different parasite genes during development based in reverse genetics. More current data revealed that TcPRAC may participate in the mechanisms of D-proline addition into recently formed polypeptide chains contributing to parasite evasion. Present proteomic approches of the group include the identification of D-proline bearing parasite proteins. We have recently obtained the crystallographic structure of TcPRAC, defined the catalytic mechanism of the enzyme and associated its B- cell mitogenic property to TcPRAC epitopes that undergo significant conformational changes upon inhibitor binding. Ongoing studies aim at designing enzyme inhibitors to be used in therapeutic approaches. Our studies aim at reveal potential strategies for immuno- and therapeutic interventions in Chagas' patients.

Michael Nilges, Arnaud Blondel, L. Masgrau, Institut Pasteur de Paris, France
Yves Janin, Institut Pasteur de Paris, France
Catherine Rougeot, Institut Pasteur, Paris, France
Pedro Alzari, Institut Pasteur de Paris, France
Mohamad Afshar, ArianaPharma
Tania Araujo Jorge, FIOCRUZ, Rio de Janeiro, Brasil
Wim Degrave, Marcelo Alves, Nazareth Meirelles, FIOCRUZ, Rio de Janeiro, Brasil

Publications :

Crystal Structure, Catalytic Mechanism and Mitogenic Properties of Trypanosoma cruzi Proline Racemase.Buschiazzo, A., Goytia, M., Schaeffer, F., Degrave, W.M., Shepard, W., Grégoire, C., Chamond, N., Cosson, A., Berneman, B., Coatnoan, N., Alzari, P., PP. Minoprio. Proc. Nat. Acad. Sci. 103, 1705-1710 (2006)

Trypanosoma cruzi proline racemases are involved in parasite differentiation and infectivity. Chamond, N., Goytia, M, Coatnoan, N., Barale, J.C., Cosson, A., Degrave, W.M., Minoprio, P. Mol. Microbiol 58, 46-60, (2005)

Biochemical characterization of proline racemases from the human protozoan parasiteTrypanosoma cruzi and definition of putative protein signatures. N. Chamond, C. Grégoire, N. Coatnoan, C. Rougeot, L.H. Freitas-Junior, J. F. da Silveira, W.M. Degrave and P. Minoprio. 2003. J. Biol. Chem. 278 : 15484-15494

Increased Trypanosoma cruzi invasion and heart fibrosis associated with high TGFß-levels in mice deficient in alpha-2 macroglobulin. M.C., Waghabi, C.M.L.M. Coutinho, M.N.C. Soeiro, M.C.S. Pereira, J.J. Feige, M. Keramidas, A. Cosson, P. Minoprio, F. Van Leuven, and T.C. Araújo-Jorge. 2002. Infect. Immun. , 70: 5115-5123.

Immunotherapy of Trypanosoma cruzi infections. N. Chamond, N. Coatnoan and P. Minoprio. 2002. Curr. Drugs Targets. 2: 247-254

Significant association between the skewed natural antibody repertoire of xid mice and resistance to Trypanosoma cruzi infection. E. C. Santos.Lima, R. Vasconcelos, B. Reina.San.Martin, C. Fesel, A. Cordeiro.da.Silva, A. Berneman, A. Cosson, A. Coutinho and P. Minoprio. 2001. Eur. J. Immunol. 31 : 634-645.

Parasite polyclonal activators: new targets for vaccination approaches? P. Minoprio. 2001. Internat. J. Parasitol.31 : 588-591

A B-cell mitogen from a pathogenic trypanosome is a eukaryotic proline racemase. B. Reina-San-Martin, W. Degrave, C. Rougeot, A. Cosson, N. Chamond, A. Cordeiro-da-Silva, M. Arala-Chaves and P. Minoprio. 2000. Nature Medicine. 6 : 890-897.
- See also commentary in News and Views, "A B-cell activator in Chagas disease", Nature Med. Vol. 6 No. 8, p 865-866 (2000), by Dr. John Kelly. Press release ; Communiqué de presse ; Comunicado de imprensa.

Lymphocyte polyclonal activation: a pitfall for vaccine design against infectious agents. B. Reina-San-Martin, A. Cosson and P. Minoprio. 2000. Parasitol. Today. 16 : 62-67.
Additional references to our paper entitled "Lymphocyte Polyclonal Activation : a Pitfall for Vaccine Design against Infectious Agents" in Parasitology Today Vol. 16, No 2, p 62-67, 2000, by B. Reina-San Martin, A. Cosson and P. Minoprio.

Changes in the cytokine profile of lupus-prone (NZB/NZW)F1 induced by Plasmodium chabaudi and their implications in the reversal of clinical symptoms. M. N. Sato, P. Minoprio, S. Avrameas and T. Ternynck. 2000. Clin. Exp. Immunol. 119 : 333-339.

A Trypanosoma cruzi alkaline antigen induce polyclonal B cell activation of normal murine spleen cells by T-cell-independent, BCR-directed stimulation. C. Montes, E. Zuniga, P. Minoprio, E. Vottero-de-Cima and A. Gruppi. 1999. Scan. J. Immunol. 50 : 159-166.

Theileria annulata in CD5-positive macrophages and B1 B cells. M. F. Moreau, J. L. Thibaud, L. B. Milled, M. Chaussepied, M. Baugartner, W. C. Davies, P. Minoprio and G. Langsley. 1999. Infect. Immunity. 67 : 6678-6682.

X-linked immunodeficiency affects the outcome of Schistosoma mansoni infection in the murine model. S. Gaubert, A. Viana-da-Costa, C. A. Maurage, E. C. S. Lima, J. Fontaine, S. Lafitte, P. Minoprio, A. Capron and J. M. Grzych. 1999. Parasite Immunol. 21 : 89-101.

A 24 kDa Trypanosoma cruzi antigen is a B cell activator. A. Cordeiro.da.Silva, A. Guevara.Espinoza, A. Taibi, A. Ouaissi and P. Minoprio. 1998. Immunology. 94 : 189-196.

Evidence for a protective role of tumor necrosis factor in the acute phase of Trypanosoma cruzi infection in mice. E. C. Santos-Lima, I. Garcia, M.-H. Vicentelli, P. Vassalli and P. Minoprio. 1997. Infect. Immun. 65 : 457-465.

Chagas' disease is attenuated in mice lacking gd T cells. E. C. Santos-Lima and P. Minoprio. 1996. Infec. Immun. 64 : 215-221.

Vb6-bearing cells are involved in resistance to Trypanosoma cruzi infection in XID mice. A. Cordeiro-da-Silva, E. C. S. Lima, M.-H. Vicentelli and P. Minoprio. 1996. Internat. Immunol. 8 : 1213-1219.

The influence of T cell subsets on Trypanososma cruzi multiplication in different organs. M. Russo, N. Starobinas, M. C. Garibaldi.Marcondes, P. Minoprio and M. Hontebeyrie-Joskowicz. 1996. Immunol. Letters. 49 : 163-168.

Ig-Isotypes patterns of primary and secondary B cell responses to Plasmodium Chabaudi Chabaudi correlate with IFN-g and IL-4 cytokine production and with CD45RB expression by CD4+ spleen cells. M. R. d'Imperio-Lima, J. M. Alvarez, G. C. Furtado, T. L. Kipnis, A. Coutinho and P. Minoprio. 1996. Scand. J. Immunol. 43 : 263-270.

Murine ascariasis. II. Immunological dysfunction and evidence for chronic activation of Th2 lymphocytes. P. Jungman, A. Freitas, A. Bandeira, A. Coutinho and P. Minoprio. 1996. Scand. J. Immunol. 43 : 604-612.

Intranasal inoculation of Bordetella bronchiseptica in mice induces long lasting antibody immune responses. P. Gueirard, P. Minoprio and N. Guiso. 1996. Scand. J. Immunol. 43 : 263-270.

Defects in the regulation of anti-DNA antibody production in aged lupus-prone (NZB x NZW)F1 mice : analysis of T cell cytokine synthesis. M. Sato, P. Minoprio, S. Avrameas and T. Terninck. 1995. Immunology. 85 : 26-32.

The relative impact of bacterial virulence and host genetic background on cytokine expression during Mycobacterium avium infection of mice. A. G. Castro, P. Minoprio and R. Appelberg. 1995. Immunology. 85 : 556-561.

In vivo evidence of a non-T cell origin of interleukin 5. A. G. Castro, P. Minoprio and R. Appelberg. 1995. Scand. J. Immunol. 41 : 288-292.

Endogenous IL-10 and IFN-g production controls thymic cell proliferation in mice acutely infected by Trypanosoma cruzi. M. d. C. Leite-de-Moraes, P. Minoprio, M. Dy, M. Dardenne, W. Savino and M. Hontebeyrie-Joskowicz. 1994. Scand. J. Immunol. 39 : 51-58.

Skewed Vb TCR repertoire of CD8+ T cells in murine Trypanosoma cruzi infection. M. d. C. Leite-de-Moraes, A. Coutinho, M. Hontebeyrie-Joskowicz, P. Minoprio, H. Eisen and A. Bandeira. 1994. Int. Immunol. 6 : 387-392.

Role of gamma interferon and tumour necrosis factor alpha during T-cell-independent and -dependent phases of Mycobacterium avium infection. R. Appelberg, A. G. Castro, J. Pedrosa, R. Silva, I. Orme and P. Minoprio. 1994. Infec. Immunity. 62 : 3962-3971.

Role of IL-6 in the induction of protective T cells during mycobacterial infections in mice. R. Appelberg, A. G. Castro, J. Pedrosa and P. Minoprio. 1994. Immunology. 82 : 361-364.

Murine AIDS protects mice against experimental cerebral malaria: down regulation by IL-10 of a Th1 CD4+ mediated pathology. M. Eckwalanga, M. Marussig, M. Dias.Tavares, J. C. Buanga, E. Hullier, J. Pavlovitch, P. Minoprio, D. Portnoi, L. Renia and D. Mazier. 1994. Proc. Nat. Acad. Sci. 91 : 8097-8101.

Increase of B lymphocyte numbers and activity during experimental murine schistosomiasis mansoni. M. C. E. Cheikh, H. Dutra, P. Minoprio and R. Borojevic. 1994. Bra. J. Biol. Res. 27 : 1605-1617.

Xid-associated resistance to experimental Chagas'disease is IFN-g-dependent. P. Minoprio, M. Cury-El-Cheikh, E. Murphy, M. Hontebeyrie-Joskowicz, R. Coffman, A. Coutinho and A. O'Garra. 1993. J. Immunol. 151 : 4200-4208.

Chagas' disease : Trypanosoma cruzi versus the host immune system. M. Hontebeyrie-Joskowicz and P. Minoprio. 1991. Res. Immunol. 142 : 125-126.

V-region-related and -unrelated immunosuppression accompanying infections. M. Arala-Chaves, M. R. d'Imperio-Lima, A. Coutinho, C. Pena-Rossi and P. Minoprio. 1992. Mem. Inst. Osw. Cruz. 87 : 35-41.

CD5 B cells: Potential role in the (auto)immune responses to Trypanosoma cruzi infection. M. Cury-El-Cheikh, M. Hontebeyrie-Joskowicz, A. Coutinho and P. Minoprio. 1992. Ann. New York Acad. Sci. 651 : 557-569.

Xid immunodeficiency imparts increased parasite clearance and resistance to pathology in experimental Chagas'disease. P. Minoprio, A. Coutinho, S. Spinella and M. Hontebeyrie-Joskowicz. 1991.Internat. Immunol. 3 : 427-433.

Chagas'disease: CD5 B-cell dependent Th2 pathology? P. Minoprio. 1991. Res. Immunol. 142 : 137-140.

Is TNFa involved in early susceptibility of Trypanosoma cruzi-infected C3H/He mice? N. Starobinas, M. Russo, P. Minoprio and M. Hontebeyrie-Joskowicz. 1991. Res. Immunol. 142 : 117-122.

Immunobiology of murine T. cruzi infection: the predominance of parasite-nonspecific responses and the activation of TcRI T cells. P. Minoprio, S. Itohara, C. Heusser, S. Tonegawa and A. Coutinho. 1989. Immunol. Rev. 112 : 183-207.

Indiscriminate representation of VH-gene families in the murine B lymphocyte responses to Trypanosoma cruzi. P. Minoprio, L. Andrade, M.-P. Lembezat, L. S. Ozaki and A. Coutinho. 1989. J. Immunol. 142 : 4017-4021.

Preferential expansion of Ly1-B and CD4- CD8- T cells in the polyclonal lymphocyte responses to murine Trypanosoma cruzi infection. P. Minoprio, A. Bandeira, P. Pereira, T. A. Mota-Santos and A. Coutinho. 1989. Intern. Immunol. 1 : 176-184.

Susceptible mice present higher macrophage activation than resistant mice during infections with myotropic strains of Trypanosoma cruzi. M. Russo, N. Starobinas, R. Ribeiro-dos-Santos, P. Minoprio, H. Eisen and M. Hontebeyrie-Joskowicz. 1989. Paras. Immunol. 11 : 385-395.

Most B cells in acute Trypanosoma cruzi infection lacks parasite specificity. P. Minoprio, O. Burlen, P. Pereira, B. Guilbert, L. Andrade, M. Hontebeyrie-Joskowicz and A. Coutinho. 1988. Scand. J. Immunol. 28 : 553-561.

Parasitic load increases and myocardial inflammation decreases in Trypanosoma cruzi- infected mice after inactivation of helper T cells. M. Russo, N. Starobinas, P. Minoprio, A. Coutinho and M. Hontebeyrie-Joskowicz. 1988. Ann. Inst. Pasteur/ Immunol. 139 : 225-236.

Depletion of L3T4 T lymphocytes during Trypanosoma cruzi infection inhibits macrophage and B lymphocyte activation but not tissue inflammatory reaction. M. Russo, P. Minoprio, A. Coutinho, H. Eisen and M. Hontebeyrie-Joskowicz. 1988. Mem. Inst. Osw. Cruz. 83 : 527-538.

Suppression of polyclonal antibody production in Trypanosoma cruzi infected mice by treatment with anti-L3T4 antibodies. P. Minoprio, H. Eisen, M. Joskowicz, P. Pereira and A. Coutinho. 1987. J. Immunol. 139 : 545-550.

Lymphocyte activity in mice infected with Trypanosoma cruzi. P. Minoprio, M. R. d. I. Lima, P. Araujo, M. Joskowicz, H. Eisen and A. Coutinho. 1986. In Parasitic infections, immunology and micotic infections, General Topics. Eds. W. Marget W. Lang, E. Gabler Sandberger, Vol. III : 237-239.

Persistance of polyclonal B cell activation with undetectable parasitemia in late stages of experimental Chagas'disease. M. R. d'Imperio-Lima, H. Eisen, P. Minoprio, M. Joskowicz and A. Coutinho. 1986. J. Immunol. 137 : 353-356.

Polyclonal lymphocyte responses to murine Trypanosoma cruzi infection. II. Cytotoxic T lymphocytes. P. Minoprio, A. Coutinho, M. Joskowicz, M. R. d. I. Lima and H. Eisen. 1986. Scand. J. Immunol. 24 : 669-679.

Polyclonal lymphocyte responses to murine Trypanosoma cruzi infection. I. Quantitation of both T and B cell responses. P. Minoprio, H. Eisen, L. Forni, M. R. d'Imperio-Lima, M. Joskowicz and A. Coutinho. 1986. Scand. J. Immunol. 24 : 661-668.

Cette équipe a comme thème de recherches, l’étude des mécanismes immunitaires déclenchés lors d'un processus infectieux pouvant être responsables de l’immunosuppression et de l'échappement du parasite. Le modèle expérimental étudié, responsable de la Maladie de Chagas (Carlos Chagas, 1909), est celui de l’infection murine par le parasite Trypanosoma cruzi.

La Maladie de Chagas, découverte par Carlos Chagas en 1909, est due au parasite protozoaire Trypanosoma cruzi,et représente un problème de santé publique en Amérique latine. Parmi 360 millions de personnes vivant en zone d’endémie, 90 millions d’individus sont à risque et 16-18 millions sont infectés. Le contrôle de la transmission vectorielle par des insecticides a été entamé avec succès dans la zone du Cône Sud (Argentine, Brésil, Chili, Uruguay). Cependant, les connaissances des mécanismes immunitaires impliqués dans la pathologie chronique progressive posent encore un défi pour le développement des stratégies efficaces de protection contre l’infection ou contre l’agression tissulaire. L'infection chronique est incurable, peut être invalidante et parfois mortelle.