[Generation of suppressive protein after heavy physical stress in athletes]

Our previous work showed that under the condition of restraint stress and the control of central nervous system, a suppressive protein (neuroimmune protein, NIP) was generated in peripheral lymph tissue and released into the blood stream, which acts as an immune suppressor. In the present study the serum from the athletes performed a heavy athletic training for 18 days was also able to suppress the lymphocyte proliferation of normal mice. The molecular weight at the suppressive factor in athlete serum determined by gel filtration HPLC was similar to that in mice and rats. In vitro experiment, the normal human lymphocytes were incubated with the serum from restraint stressed rats for 12 h and then the extract of human lymphocyte was made for testing the effect on normal lymphocyte proliferation. The result showed that it suppressed normal mouse lymphocyte proliferation. This result was similar to our previous experiment by using normal mouse lymphocyte incubated with the rat serum treated with restraint stress. It was also found that the serum and the extract of lymph node from restraint stressed mice suppressed human lymphocyte proliferation induced by PHA. The results suggest that suppressive protein induced by stress in mice and rats could also be induced in human beings and there is no distinct species specificity among them.