Monoclonal Antibodies against Murine Neonatal and Pregnancy-Associated Natural Suppressor Cells Induce Resorption of the Fetus (original) (raw)

Pregnant and neonatal/l'ctal mice have been shown to harbour niuurnlly occurring inhibitory cells ot" both T and non-T type. Non-T suppressor ceils present in the spleen of priniipurous pregnant and newborn animals inhibit proliferative responses in auinlogous and aliogcneie mixed lymphocyte reactions. Sueh cells can be positively selected for hy agglutination with the B cell-specific lectin soybean agglutinin (SBA). We generated rat IgG monoclonal antibodies against unique cell surface structures on the non-T inhibitory cells, and cylotoxic pretreatment of spleen cells from pregnant or neonaial/felal mice largely abrogates iheir suppressive activity on proliferative responses. Furthermore, in vivo administration of such antibodies to pregnant inbred and oulbred mice results in termination of the pregnancy or decreased litter size. Since injection of anti-T cell igO monoclonal antibodies does not interfere with the delivery of normal sized litters it is evident from these studies that the non-T immunoregulatory cells, in contrast to T-inhibitory cells, are of greal importance in ensuring immunological homeostasis in the fetat-placental environment during pregnancy in mice.