CHANGES IN B CELL SUBSETS DURING TRYPANOSOMA CRUZI INFECTION AND THEIR RELATIONSHIP WITH THE ANTIBODIES (Abs) PROFILE.

Bermejo D, Acosta-Rodriguez E*, Merino C*, Montes C*, Gruppi A. CIBICI. FCQ-UNC

The production of Abs depends on mature B cells which are classified as conventional (B2), CD5+ (B1) and marginal zone (MZ) B cells. These B cell subsets present different phenotypes and contribute to the humoral response with differential Ab repertoire. To evaluate the changes in B cell subsets and their relationship with the Abs response during T. cruzi infection, we studied the spleen, bone marrow, and peritoneum of Balb/c mice non-infected or infected with 500 tripomastigotes of T. cruzi. In spleen, B cell subsets were identified by FACS based on the differential expression of IgM, IgD, CD21, CD23, CD24, and Syndecan-1. We observed a decrease in the percentage of MZ B cells at 18-25 days p.i and an increase in number of the immature (T1 and T2) and mature B cell and plasma cells between 10-25 days p.i. B cells from infected mice secrete higher levels of Abs than B cells from normal mice. Interestingly, the same profile of IgG isotypes is produced by cells from spleen and peritoneum of infected mice. In concordance with the medullar hypoplasia no increase in Ab production was observed in infected mice. Independent of environment the T cruzi infection induces the same profile of Abs in the different niches of the humoral response.

*These authors contributed equally to this work