Selective expression of class II MHC isotypes by MLC-activated human T lymphocytes.
Although activated human T cells express class II MHC molecules, the biologic significance of this event is not understood. Using two-color flow cytometry, we have analyzed the expression of HLA-DR, -DQ, and -DP isotypes by T cells following activation by allogeneic lymphoblastoid B-cell lines. Within the CD3+ population, transient expression was observed at 1 day following initiation of culture, which preceded a dramatic and sustained increase around 6-7 days. DR expression was always highest, followed by DP and DQ with DP expression usually somewhat higher than DQ. At day 8, three populations were observed consisting of DR+DP+DQ+ (60%), DR+DP+ (69%), and DR+ (75%) T cells. Interestingly, DQ+ or DP+ but DR- T cells were not observed. These patterns of class II isotype expression were similar in CD2+, CD4+, and CD8+ subgroups and suggest that class II molecules are selectively expressed on T cells and may play a role in the regulation of T-cell responses to alloantigens.
Oshima
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Immunogenetics Research Section, Blood Center of Southeastern Wisconsin, Milwaukee 53233.
Eckels
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D000911:Antibodies, Monoclonal / Q000276:immunology; D002455:Cell Division; D002461:Cell Line, Transformed; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D005453:Fluorescence; D000949:Histocompatibility Antigens Class II / Q000096:biosynthesis*; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007700:Kinetics; D007962:Leukocytes / Q000276:immunology; D008213:Lymphocyte Activation; D013601:T-Lymphocytes / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000949:Histocompatibility Antigens Class II; D007376:Interleukin-2