[Development of various forms of immunosuppression after exertion and heat exposure]

In Wistar rats, 3-hour moderate exercise precipitated the development of antigen-specific immunosuppression induced by large doses of sheep erythrocytes, while 5-hour exercise caused, in addition, the development of antigen-nonspecific immunosuppression. After 5-hour swimming splenic cells which did not adhere to the plastic secreted the antigen-specific factor (ASF), while cells adhering to the plastic secreted the antigen-nonspecific factor (ANSF). Immunosuppressive ASF had no effect on ANSF secretion, whereas the latter accelerated the secretion of ASF by the splenocytes of swimming rats. Administration of erythrocytes of swimming rats induced the secretion of immunosuppressive ANSF by splenic cells which adhered to the glass and this factor promoted ASF secretion in hyperimmunized rats. After warming, the erythrocytes lost their property of inducing ANSF secretion by cells which did not adhere to the glass, which led to secondary diminution of ASF secretion.