Analysis of proliferating lymphocyte subpopulations in newborns and adults.

Surface markers of peripheral lymphocyte subpopulations were determined before and after in vitro stimulation of neonatal and adult mononuclear cells with phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). The type of cell responding to each mitogen was identified by a method combining autoradiography and the peroxidase-antiperoxidase (PAP) staining method. In comparison with adults, there is a lower proportion of OKT3-positive lymphocytes in neonates (43% vs. 72%). Analysis of lymphocyte subpopulations after stimulating mononuclear cells with PHA and PWM showed that in neonates nearly the same percentages of OKT4-and OKT8-positive proliferating cells (43% and 40%, respectively) could be observed, whereas in the proliferating cells from the adults, the OKT8 surface marker predominated (41% vs. 18%).