LYMPHOCYTE-PROLIFERATION IN RESPONSE TO EXERCISE

Lymphocyte proliferative responses are often used to evaluate the func tional capacity of the immune system in response to exercise. Blood mo nonuclear cells (BMNC) are stimulated in vitro with polyclonal mitogen s and the incorporation of H-3-thymidine into the DNA reflects cell pr oliferation. The BMNC are most often stimulated with either phytohaema gglutinin (PHA), poke weed mitogen (PWM), concanavalin A (Con-A), inte rleukin-2 (IL-2), or purified derivative of tuberculin (PPD). The lite rature concerning lymphocyte proliferation and exercise is reviewed wi th respect to the type and intensity of exercise, and also the effect of training status. The proliferative responses to exercise are highly heterogeneous, the most consistent finding being that PHA-stimulated cell responses decrease during exercise which may reflect a decreased fraction of CD3+ cells. In contrast, reduced, elevated or even unchang ed lymphocyte proliferative response to PHA, PWM, Con-A, IL-2 and PPD have been demonstrated in the recovery period following exercise. Also variable responses are present in trained athletes compared to less f it subjects. Even though this may reflect that the time of H-3-thymidi ne incorporation into lymphocytes varies, we conclude that a functiona l evaluation of the immune system in response to exercise cannot be ba sed solely upon measurements of lymphocyte proliferation.