GRANULATED LYMPHOCYTES OF PREGNANCY

In pregnant mammals, the antigenically distinctive conceptus implants and grows in a uterine environment governed by the maternal immune sys tem. The uterus per se is not immunologically privileged and large num bers of lymphocytes accumulate at implantation sites. Tn mice and huma ns, many of these lymphocytes hare been identified as uterine natural killer (uNK) cells and exhibit a characteristic granulated morphology. In this review we focus on uNK cells and discuss their origin, differ entiation and possible roles in the maintenance of healthy pregnancies . In species with less invasive placentation (ruminants, pigs), lympho cytes with similar granular morphology also appear during gestation an d their identity and possible functions are examined. (C) 1996 W.B. Sa unders Company Ltd