Two different biosynthetic pathways for the secretion of Qa region-associated class I antigens by mouse lymphocytes.
Treatment of supernates of labeled C57BL/6 mouse lymphocytes with antibodies against beta 2-microglobulin reveals the presence of two different soluble class I molecules. One molecule (Mr, 37,000) is found in supernates of both 125I surface-labeled and [35S]methionine biosynthetically labeled cells and reacts with antibodies against Qa-2 antigens. The other molecule (Mr, 42,000) is found labeled only in supernates of [35S]methionine-labeled cells and reacts with antibodies against Qb-1. Analysis of mutant and recombinant mouse strains demonstrates that both soluble class I molecules are encoded in the Qa region. Pulse-chase experiments show that the Qa-2 molecules are released more slowly than Qb-1. It is proposed that Qb-1 molecules are secreted directly, whereas Qa-2 is first expressed on the cell surface and then processed to a soluble form.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis / Q000235:genetics*; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D006649:Histocompatibility Antigens / Q000032:analysis / Q000235:genetics*; D015395:Histocompatibility Antigens Class I; D007525:Isoelectric Focusing; D008715:Methionine / Q000378:metabolism; D051379:Mice; D008815:Mice, Inbred Strains; D008970:Molecular Weight; D009154:Mutation; D013601:T-Lymphocytes / Q000276:immunology*
D000954:Antigens, Surface; D006649:Histocompatibility Antigens; D015395:Histocompatibility Antigens Class I; C032907:Q surface antigens; D008715:Methionine