Cellular immune aspects of the human fetal maternal relationship. II. In vitro response of gravida lymphocytes to phytohemagglutinin

At optimal doses of phytohemagglutinin, human gravida lymphocytes showed no depression of responses when compared to nonpregnant female control lymphocytes. Compared to the control cells, gravida lymphocytes also seemed to have a higher spontaneous incorporation, a higher response at suboptimal PHA concentrations, and a lower peak dose response. These findings were more evident in the latter third of the pregnancy and suggest that maternal lymphocytes by this test are apparently fully reactive, and that they are undergoing low-level stimulation.