title: Alloantisera with apparent HLA-A specificity reacting only against phytohemagglutinin-activated cells.
abstract: Seven alloantisera were selected showing the following characteristics: after platelet absorption they were positive with PHA-activated cells and negative with resting T and B lymphocytes from the same donors; this reactivity could be blocked by pretreatment of cells with a turkey anti-human beta 2-microglobulin serum and was not completely removed by further absorption with high doses of pooled platelets or with T or B lymphocytes from the positive donors; the reactivity of some of these antisera correlated with HLA-A antigens in a panel of PHA-activated cells and segregated with HLA haplotypes in families. It is still to be proven if the HLA determinants recognized on PHA-activated cells by these antisera are new epitopes of A,B,C molecules appearing upon activation or if they are carried by products of a new polymorphic locus linked to the HLA system.
mesh_terms: D001402:B-Lymphocytes / Q000276:immunology*; D000939:Epitopes / Q000032:analysis; D008040:Genetic Linkage; D006680:HLA Antigens / Q000032:analysis* / Q000235:genetics; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000939:Epitopes; D006680:HLA Antigens; D007106:Immune Sera; D010835:Phytohemagglutinins