Increased immunoglobulin secretion by B lymphocytes from Trypanosoma cruziinfected mice after B lymphocytes-natural killer cell interaction

In the present study, we investigated whether natural killer (NK) cells mod ulate immunoglobulin (Ig) secretion by B cells from Trypanosoma cruzi-infec ted mice. B cells from infected mice increased IgM and IgG2a secretion in t he presence of a NK cell line, and this response was cell contact-dependent . Stimulation of splenic B cells with polyinosinic-polycytidylic acid, a NK cell activator, also increased Ig secretion by B cells from infected mice. B cells from infected mice expressed higher levels of the B7.2 molecule. O ur results suggest that NK cells may be involved in the control of the abno rmal B cell activation observed during T. cruzi infection.