title: Frequency of alloantibodies reacting with PHA-activated T lymphocytes, unexplainable by known HLA activities.
abstract: Two hundred and three sera obtained from multiparous women were screened to determine the frequency of the appearance of antibodies reactive with PHA-activated T lymphocytes, but not with resting B or T cells from the same donor. The panel of cells on which the sera were tested consisted of lymphocytes from 38 unrelated donors known to be homozygous at the HLA-D locus. Forty-two sera were shown to react uniquely with PHA-activated T cells. The reactivities of these sera could not be explained in terms of the defined HLA-A,-B,-C, or DR antigen specificities on the panel cells, nor on the basis of known cross-reactivities among these antigens. Most of the antisera showed strong cytotoxicity with the activated T cells. Such sera may define antigens presented to the maternal immune system during differentiation and development, which are not expressed on adult T cells unless they are activated.
mesh_terms: D000818:Animals; D005260:Female; D006680:HLA Antigens; D006720:Homozygote; D006801:Humans; D007106:Immune Sera / Q000494:pharmacology; D007518:Isoantibodies; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology*; D011817:Rabbits; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D006680:HLA Antigens; D007106:Immune Sera; D007518:Isoantibodies; D010835:Phytohemagglutinins