CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
B CELLS INFLUENCE CD8+ T CELL RESPONSE IN TRYPANOSOMA CRUZI INFECTION
Autor/es:
FIOCCA VERNENGO, FACUNDO; GOROSITO SERRAN, MELISA; TOSELLO BOARI, JIMENA; BECCARIA, CRISTIAN G; RAMELLO, MARIA CECILIA; MONTES, CAROLINA LUCIA; ACOSTA RODRIGUEZ E V; GRUPPI, ADRIANA
Lugar:
Los Cocos
Reunión:
Jornada; LXI Reunión Anual de la sociedad argentina de Inmunología .; 2013
Institución organizadora:
Sociedad Argentina de Inmunologia
Resumen:
B CELLS INFLUENCE CD8+ T CELL RESPONSE IN TRYPANOSOMA CRUZI INFECTION
Fiocca
Vernengo, Facundo ; Gorosito
Serran, Melisa ; Tosello Boari, Jimena ; Beccara, Cristian Daniel ; Ramello,
Cecilia ; Acosta Rodriguez, Eva ; Montes, Carolina ; Gruppi, Adriana ;
Departamento de Bioquímica Clínica e Inmunología, FCQ, UNC
CD4+ T cells expressing CD25 and Foxp3 (Tregs) regulate immune responses
and, consequently, influence the pathogenesis of infectious diseases.
Regulatory response during T. cruzi infection has been poorly characterized and
Treg roles remain controversial after few studies based on Treg depletion and
GITR and CTLA-4 blockade. Our aim is to characterize the magnitude and quality
to further elucidate the role of Treg response during experimental T. cruzi
infection. For this, Foxp3-GFP mice were infected with 5000 T. cruzi
tripomastigotes and Tregs (GFP+CD4+CD25+ cells) were enumerated and
characterized at different days (d) postinfection (pi) by flow cytometry. The
absolute numbers of Tregs remained constant or were slightly increased in all
the organs studied while the numbers of effector subsets regulated by Tregs
(i.e. CD4 and CD8 T cells and B cells) were greatly augmented in spleen, lymph
nodes and liver but not in thymus. Thus, the ratio of Tregs to effector cells
was significantly diminished in the periphery from d10 until d60pi (early chronic
phase, last day of study) (spleen: d0pi 0.134±0.012 vs d20pi 0.056±0.008,
p<0.005; and d60pi 0.081±0.008, p<0.01). In contrast, Tregs were
overrepresented in thymus. Phenotypic profiling of Tregs showed that some
characteristics such as CD44hiCD62LlowCD127lowCD73hi were conserved during
infection whereas other markers as CD103 and CTLA-4 were significantly
upregulated. Of note, a fraction of Tregs expressed CXCR3 and produced IFNg
upon infection showing plastic attributes. Analysis of putative markers of
thymic origin at d15pi showed that the percentage of Tregs expressing Helios
remained unchanged but Neuropilin-1 expression was significantly downregulated.
Our results suggest that Tregs are activated during T. cruzi infection but the
number of Tregs is overwhelmed by the number of effector cells. This may be
associated with the tissue damage observed. Our data provide a rationale for
enhancing Treg response to prevent immunopathology.