Human T cells in cord blood: abnormalities in IA antigens induction by phytohemagglutinin and in autologous mixed lymphocyte reactions.
About 25% of human T cells isolated from cord blood acquired la antigens, following stimulation with phytohemagglutinin (PHA) for 72 hr. This percentage is markedly lower than that found in PHA-activated T-cell populations (PHA-T cells) isolated from peripheral blood of adults. The low expression of la antigens by human T cells from cord blood does not reflect abnormalities in the sensitivity to PHA stimulation and/or in the kinetics of induction of la antigens. PHA-T cells from cord blood display a low stimulatory activity in autologous mixed lymphocyte reactions (MLR). The defect does not reflect a nonspecific abnormality in the stimulatory activity of PHA-T cells from cord blood, since the latter do not differ from PHA-T cells from adults in their ability to stimulate allogeneic T cells from adults. Furthermore the defect does not reflect a nonspecific abnormality in the proliferative response of T cells from cord blood, since the latter display a normal proliferative response to PHA-T cells from adults. The defect in the proliferative response is not restricted to the autologous MLR with PHA-T cells, since it was found also in autologous MLR with non-T cells as stimulators. Correlation of the temporal evolution of the abnormalities of human T cells with the maturation of the immune system may contribute to our understanding of the role of la antigens in cell-cell interactions and of the biological significance of abnormalities of autologous MLR.
D002478:Cells, Cultured; D004261:DNA Replication; D005260:Female; D005312:Fetal Blood / Q000276:immunology*; D005802:Genes, MHC Class II; D000949:Histocompatibility Antigens Class II / Q000032:analysis*; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D009000:Monocytes / Q000276:immunology; D011247:Pregnancy; D013601:T-Lymphocytes / Q000276:immunology*
D000949:Histocompatibility Antigens Class II