Pregnancy Immunology

The diverse papers addressing immune responses, specific and nonspecific, within the local uterine environment, as well as in extra-uterine sites, presented in this session of the Third Annual International Symposium on the Immunology of Reproduction were based on studies conducted utilizing those techniques which gained standard usage in the decade 1970 to 1980. In this section, investigators presented the results of studies which examined cellular and humoral immune mechanisms operating in the local uterine environment; alterations in systemic maternal immunoreactivity, both that which is specific to the conceptus and that which is nonspecific; and activities of sets and subsets of immunoreactive cells studied both before and during pregnancy. In the animal studies, local immunoreactivity within the uterus was assessed. M. Kearns and P. Lala (Am J Reprod Immunol issue 3:2) claim that uterine decidual cells in pseudopregnant mice were of bone marrow origin. They produced bone marrow chimeras by repopulating lethally irradiated FI hybrid mice and identified decidual cells bearing donor-specific antigens utilizing an immunolabeling technique with monospecific anti-H2 antibodies. This interesting finding requires confirmation; however, the possibility that decidual cells have immune functions necessary for the maintenance of pregnancy is exciting. J.P. Krcek and his associates studied the accumulation of mononuclear cells in the vicinity of the trophoblastic giant cells in the pregnant mouse uterus. The infiltrate was more pronounced on the tenth day of pregnancy in matings with H2 haplotype differences. The fact that the mononuclear leukocyte accumulation was localized to the implantation site supports the concept of immunological recognition on an antigen-specific basis. R.N. Smith and his associates analyzed the maternal alloantibody response in allogenic pregnancies in rats. The primary and secondary alloantibody response following pregnancy were quite different from alloantibody responses following conventional alloimmunization. During pregnancy, the predominant source of the alloantibody was found to be in the spleen and was specific towards the conceptus. D.A. Clark and R.M. Slapsys (Am J Reprod Immunol issue 3:2) previously documented the presence of suppressor cells in lymph nodes draining the uterus of allogenically mated mice. Further studies showed that these cells appeared first in the uterine decidua after mating and reached their maximum concentration at the time of implantation. Their suppressive activity was not specific for the paternal MHC antigens but selectively inhibited the generation of cytotoxic T lymphocytes.