Inability of newborns' or pregnant women's monocytes to suppress pokeweed mitogen-induced responses.
Although an excess of human adult blood adherent cells inhibits the pokeweed mitogen- (PWM) induced normal adult lymphocyte proliferation and B cell maturation into immunoglobulin-containing cells (ICC), adherent cells collected from newborn infants or pregnant women at time of delivery were unable to exert a similar suppressor activity. After activation by Concanavalin A (Con A), newborns' and pregnant women's adherent cells acquired a suppressor activity comparable to that of control adult adherent cells. The adherent suppressor cell was shown to be radioresistant (3000 rad), indicating its probable monocytic origin. Both monocyte-suppressor activities (MSA) observed in adulthood (spontaneously) and in the neonatal period (after activation) were dependent on prostaglandin E2 (PGE2) secretion, because they were abolished by indomethacin or a specific anti-PGE2 antiserum. Expression of MSA appeared to be under a negative regulation exerted by naturally occurring T suppressor lymphocytes present in the blood of newborns or pregnant women, because incubation of adult monocytes or Con A-activated newborn monocytes with newborns' or pregnant women's T lymphocytes resulted in a dramatic decrease of their MSA. These results strongly suggest that the lack of MSA in the neonatal period and in late pregnancy is a consequence of activation of T suppressor lymphocytes.
D001402:B-Lymphocytes / Q000166:cytology; D002448:Cell Adhesion; D002454:Cell Differentiation; D003208:Concanavalin A / Q000494:pharmacology; D015232:Dinoprostone; D005260:Female; D005312:Fetal Blood / Q000276:immunology; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D007231:Infant, Newborn; D008213:Lymphocyte Activation; D009000:Monocytes / Q000276:immunology*; D011043:Pokeweed Mitogens / Q000494:pharmacology*; D011247:Pregnancy; D011458:Prostaglandins E / Q000276:immunology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D007106:Immune Sera; D011043:Pokeweed Mitogens; D011458:Prostaglandins E; D003208:Concanavalin A; D015232:Dinoprostone; D007213:Indomethacin