INESCAPABLE FOOTSHOCK EXPOSURE DIFFERENTIALLY ALTERS ANTIGEN-STIMULATED AND MITOGEN-STIMULATED SPLEEN-CELL PROLIFERATION IN RATS

A variety of stressors have been shown to influence specific and non-s pecific measures of immune function in laboratory animals. One of the most common tools used to evaluate lymphocyte function is the non-spec ific mitogen proliferation assay. Assessment of this function in the r at spleen has revealed profound suppression following restraint, elect ric shock, and re-exposure of animals to a fearful context. However, t here have been no studies that have compared the effects of stressor e xposure on mitogen- and specific antigen-stimulated spleen cell prolif eration. Therefore, the present study addressed this issue through exp eriments in which rats were immunized intraperitoneally with 1 mug cho lera toxin and exposed to acute (one session) or repeated (three conse cutive daily sessions) footshock. The results showed that footshock ex posure prior to immunization inhibited cholera toxin stimulated spleen cell proliferation 7 days after immunization. Acute or repeated foots hock exposure 5-7 days after cholera toxin immunization depressed non- specific spleen cell proliferation, while augmenting the proliferative response to specific antigen. From these observations it can be hypot hesized that footshock exposure either differentially regulates lympho cyte activation by clonal and polyclonal signals, and/or naive and mem ory cells react differently to stressor exposure.