B cell depletion compromises CD8+ T cell response during Trypanosoma cruzi infection

FIOCCA VERNENGO F.; BECCARIA, C.; TOSELLO BOARI J.; GOROSITO SERRÁN M.; ARAUJO FURLAN C.; ACOSTA RODRIGUEZ E.; MONTES C.; GRUPPI A.

Buenos Aires

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Inmunología; 2015

Sociedad Argentina de Inmunología

Considering that CD8+T cells play a major role in protective immunity to T cruzi infection, the factors that promote the generation and maintenance of the CD8+T cell response need to be identified. It has been reported that B cells are required for optimal CD8+T cell response in cancer (DiLillo et al J Immunol 2010) and infection (Asano et al JEM 1996). Based on this information, the aim of our work was to analyze the role of B cell on CD8+T cell response in T. cruzi infection. For that, C57BL/6 mice were intraperitoneally injected with 5ug/mL of anti-CD20 (to deplete B cells) or IgG2A control antibody. After 7 days of treatment, mice were infected with 5.000 trypomastigotes (Tulahuén strain) and CD8+T cell response was analyzed at different days post infection (pi) by flow citometry and immunofluorescence.Despite B cell depletion, we observed that splenic T cell structures were present in T. cruzi infected mice. In comparison to B cell-depleted mice, B cell-sufficient mice showed a tendency of higher number of total TCD8+ cells, being significantly on day 14pi; and higher number of T. cruzi TSKB20+ specific CD8+T cells, in the spleen and liver. We also found that B cell-depleted mice had higher percentages of naïve T cells (CD44-CD62L+) and lower percentages of the effector memory cells (CD44-CD62L+). In accordance, a high percentage of CD8+T cell from depleted mice was CD127+, denoting their naïve state.The results suggest that B cell could be necessary in the generation/maintenance of specific CD8+T cells and that may also regulate effector function.