[The mechanism of the inhibiting effect of a Yersinia pestis protein factor on the hormone-stimulated response of human thrombocytes].

: Thermostable protein factor (20000 Da) was prepared from Yersinia pestis avirulent strain EV 1290. This protein inhibited the aggregation of human platelets as well as elevation of [Ca2+], induced by different agonist. The action of this protein on platelets is accompanied by elevation of cellular cGMP levels. This factor activated guanylate cyclase suspension of human platelets. The data indicate that this protein factor of Y. pestis may possibly release in circulation during decay of bacteria and can change the physiological activity of human blood cells and contribute to the pathogenesis of plague.