Antigen characteristics strongly influenced the effects of stress on the humoral immune response in the rat

The objective of the present study was to explore whether the suppressive effect of electric stress (ES) on the immune response in rats was limited to the particular antigen given concomitantly with ES. Therefore, the influence of simultaneous exposure to stress and immunization with an unrelated antigen (keyhole limpet hemocyanin, KLH) on the humoral immune response to bovine serum albumin (BSA) was investigated. Specific anti-KLH antibody levels were also determined in rats exposed to ES and concomitantly immunized with BSA. Five daily sessions of ES or immunization with KLH 2 weeks prior to immunization with BSA did not influence the secondary humoral immune response to BSA, but concomitant exposure to ES and immunization with KLH significantly decreased it. Conversely, the primary humoral immune response to KLH was suppressed by exposure of the animals to ES at the time of immunization with KLH, as well as at the time of the immunization with BSA 2 weeks later It is suggested that the suppressive effect of ES on the humoral immune response is not specific for a certain antigen. However, the chemical and immunological characteristics of the antigens shaped the profile of stress-induced immune changes with respect to the sensitivity of the primary and secondary immune response and the duration of the effect.