POSSIBLE MECHANISMS OF THE ACTION OF LYMPHOCYTE PROLIFERATION-INHIBITORY FACTOR(S)IN RAT SERUM RECEIVING ELECTROACUPUNCTURE STIMULATION
XU HONG;FAN SHAO-GUANG(Department of Physiology,Beijing Medical University)
Previous reports showed that EA stimulation(3V,2Hz,30 min/d,5 d)in-duced the production of one or more lymphocyte proliferation-inhibitory factor(s)inthe rat serum.In this paper,the mechanisms of the action for the inhibitory factor(s)to suppress lymphocyte proliferation were studied.(1)the lymphocytes from dif-ferent immune organs of the mice were prepared and cultured with the rat serumstimulated by EA.The results show that the serum not only inhibited the mouselymphonodus T cell proliferation induced by Con A,but also inhibited the mousethymocyte and spleen T cell proliferation induced by Con A.When B cells werestimulated by LPS,the proliferative effect can also be inhibited significantly bythe rat serum stimulated by EA.This implies that the effect of the lymphocyteproliferation-inhibitory factor(s)has no specificity.(2)Incubation of the mouselymphonodus cell with serum for one hour is enough to cause an inhibitory effect onCon A stimulated lymphocyte proliferation.However,no inhibitory effect wasobserved if the mouse lymphonodus cells were incubated with Con A for 15min or3O rain before the addition of rat serum.The results demonstrate that the lympho-cyte proliferation-inhibitory factor(s)act on the early events of T lymphocyte acti-vation induced by Con A.(3)Protein kinase C(PKC)is a key link in the activa-tion of T and B lymphocyte proliferation by Con A and LPS respectively.So itwould be interesting to learn whether the inhibitory effect of the lymphocyte pro-liferation-inhibitory factior(s)is caused by the inhibition of PKC activity.It wasobserved that the serum indeed inhibits the lymphocyte proliferation induced byPMA(a PKC activator)or in combination with Ca~(2+)ionophore A23187.Theseresults suggest that the inhibitory effect of the lymphocyte proliferation-inhibitoryfactor(s)might be mediated by some direct inhibition of PKC activity or indi-rectly through PKG activated pathways.