BAFF blockade affects germinal centre architecture and heart infiltration favouring parasite replication in Experimental Chagas disease

BERMEJO, DANIELA A; AMEZCUA VESELY, MARIA CAROLINA; ACOSTA RODRIGUEZ, EVA VIRGINIA; MONTES, CAROLINA LUCIA; GRUPPI, ADRIANA

Viña del Mar

Congreso; 9th Latin American Congress of Immunology; 2009

T. cruzi infected mice develop splenic massive and persistent germinal centre and extrafollicular reactions accompanied with high seric concentration of BAFF (B cell activating factor). In this work we determined that BAFF is mainly produced by peritoneal and bone marrow cells which increases after T. cruzi infection. The response in T. cruzi  infection showed a compartmentalization with peritoneum and lymph node cells producing higher amounts of Abs than spleen and bone marrow cells. To analyze BAFF role in B cell response development in Chagas’ disease, BALB/c mice were infected with 500 tripomastigotes and injected i.p. three times/week with 150 ug of BR3:Fc to block BAFF activity, or control Ab or PBS.  BAFF blockade decreased the number of mature B cells from spleen and lymph node but not from bone marrow and peritoneum. Consistently, spleen histological studies showed that BR3:Fc treated infected mice present less number of conventional follicules and a disorganized architecture than infected mice. BAFF sustained ANA-IgG and parasite-specific IgM but not parasite-specific IgG production. BAFF blockade favored parasite replication and lymphoid infiltration in heart. Together, our results show for first time an active role for BAFF in a parasite infection shaping mature B cell repertoire and parasite control.