Innate and adaptive immune responses in a social conflict paradigm.

Social conflict stress was examined for its effects on in vitro and in vivo immunity in mice. Adaptive immunity, as measured by the generation of primary IgM antibody responses to the T-dependent antigen keyhold limpet hemocyanin, was suppressed following chronic (greater than 1 day), but not acute (less than 1 day), stress periods while the IgM response to the T-independent antigen polyvinylpyrrolidone was not affected. In vitro proliferative responses of splenocytes to the T cell mitogen concanavalin A and the B cell mitogen lipopolysaccharide were unaffected. Acute (less than 1 day) stress dramatically increased innate immunity as measured by a luminol-dependent chemiluminescence assay of phagocytic cell function. DBA/2J mice averaged a 269% increase in phagocytosis as compared to a 412% increase in C57BL/6J. This differential effect of stress on immune responsiveness indicates that alterations in innate immunity in addition to adaptive immunity should also be considered when evaluating neuroendocrine and immune interactions in response to stress.