Ia-positive stimulator cells are required in primary, but not in secondary, mixed leukocyte reactions against H-2K and H-2D differences.
The expression of I region gene products on stimulator cells in primary and secondary MLR directed against differences determined by the K or D regions of the H-2 gene complex was examined in B10-congenic mice. Treatment of the stimulator cells with anti-Ia antisera and complement (C) eliminates stimulation in primary MLR against K or D region gene products, indicating that the stimulator cells must express Ia antigens on their membranes. Further, stimulation in primary MLR against D region antigens is abolished by treatment of the stimulator cells with C and antisera against either I-A or I-E subregion products, but not by treatment of stimulator cells with C and antisera against I-J subregion products. Therefore, these stimulator cells express on their membranes both I-A and I-E subregion gene products, but not I-J subregion gene products. In contrast, in secondary MLR against K or D region gene products, treatment of stimulator cells with anti-Ia antisera and C does not abolish stimulation, indicating that Ia-negative cells can stimulate primed responder cells. These results indicate that the mechanisms of cell-cell recognition necessary in secondary MLR against K or D region gene products are different from those in primary MLR to the same products.
D000818:Animals; D002448:Cell Adhesion; D003165:Complement System Proteins; D004306:Dose-Response Relationship, Immunologic; D006183:H-2 Antigens / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D007106:Immune Sera / Q000494:pharmacology; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008805:Mice, Inbred A; D014176:Protein Biosynthesis; D013154:Spleen / Q000276:immunology
D006183:H-2 Antigens; D000949:Histocompatibility Antigens Class II; D007106:Immune Sera; D003165:Complement System Proteins