Spleen B cells from BALB/c mice are more prone to activation than C57BL/6 during a secondary immune response

ANDREA PELLEGRINI; NATALIA GUIÑAZÚ; MARÍA DEL PILAR AOKI; ISABEL CHICO CALERO; EUGENIO ANTONIO CARRERA-SILVA; NURIA GIRONES; MANUEL FRESNO; SUSANA GEA

Rio de Janeiro, Brasil

Congreso; 13th International Congress of Immunology; 2007

Sociedad Brasilera de Inmunología

There is increasing interest in the study of roles that B cells may play in regulating immune responses both in protection and pathogenesis. However, little is known about additional immune functions of B cells independently of Ab production. In this study we have assessed how the immunization with T dependent Ags in different host genetic backgrounds affect several parameters of B cells during secondary immune responses. We have previously reported that BALB/c immunized with cruzipain, induced heart autoimmunity whereas C57BL/6 mice were resistant. In a comparative study employing the same experimental model, we demonstrated that BALB/c enriched spleen B cells presented higher ability to proliferate releasing elevated levels of IL-4. Moreover, spleen of immune BALB/c mice presented an increased number of germinal center and plasma cells as well as higher expression of B cell activation markers (MHC-II, CD40, CD86). Through the employment of IL-4 or IFN-gR KO mice in this model, we provided evidence supporting the differential effect of these cytokine signals in MHC-II and CD86 expression on B cells. These findings demonstrate the influence of genetic background on B cell activation and emphasize the importance of examining B cells behaviour in the context of the specific immunogens.