Relevance of sulfated oligosaccharides of cruzipain in the immunopathogenesis of Chagas disease

L.L.SOPRANO; D.M.ACOSTA; M.R FERRERO; G.A.GARCÍA; M.I.ESTEVA; A.S.COUTO; V.G.DUSCHAK

Santa Fé -Argentina

Congreso; XXIII REUNION Científica ANUAL SOC. ARG.de Protozoología; 2009

SOC. ARG.de Protozoología

Relevance of sulfated oligosaccharides of cruzipain in the immunopathogenesis of Chagas disease   Luciana L. Soprano 1 , Diana M. Acosta 1, Maximiliano R. Ferrero1, Gabriela A. García1, Mónica I. Esteva 1, Alicia S. Couto3  and Vilma G Duschak.1 1Inst Nac Parasitol Dr Mario Fatala Chaben, ANLIS-Malbrán, Ministerio de Salud de la Nación Argentina; 2CIHIDECAR-Dpto.Q.Org., FCEN, UBA, Argentina.                   Trypanosoma cruzi contains a major cysteine proteinase, cruzipain (Cz). This lysosomal enzyme bears an unusual C-terminal domain (C-T) that contains a number of post-translational modifications and is responsible for most antibodies in natural and experimental infections. UV-MALDI-TOF MS analysis, allowed us to identify the presence of sulfated high-mannose type oligosaccharides in the C-T as a new striking feature of this molecule. In order to evaluate the immune responses to sulfated moieties on Cz, the involvement of sulfated moieties in the crossreactivity between cardiac proteins and cruzipain, BALB/c mice were immunized with purified Cz and C-T prior and after desulfation treatment. The humoral immune response to sulfates on Cz or C-T was mainly IgG2b. This reactivity was abolished when desulfated antigens were used as immunogens showing that sulfates are absolutely required for eliciting IgG2b response to Cz. A significant reduction of C-T-specific delayed-type hypersensitivity reaction in C-T-immunized mice was observed when desulfated C-T was challenged, suggesting the involvement of sulfate groups in the generation of memory T-cell responses. Moreover, immunization with C-T elicited ultrastructural abnormalities in heart tissue. Surprisingly, pathological alterations were not observed in hearts from sulfate depleted-C-T-immunized mice and a lower labeling was observed by immunoelectron microscopy using myosin-adsorbed specific policlonal anti-Cz serum. Furthermore, when BALB/c mice immunized with C-T and desulfated C-T were challenged with trypomastigotes, immunepathological enhanced responses were observed in cardiac and muscle mice tissues previously immunized with C-T. Our results highlight the relevance of sulfated groups as main components of this molecule. Ongoing assays using specific anti-sulfate antibodies will help to elucidate the involvement of sulfates in the antigenicity and crossreactivity of the molecule and/or in the immunopathogenesis of Chagas disease. Supported by CONICET-ANPCYT-UBA,.INP-ANLIS-Malbrán