Studies on the reappearance of MHC class II antigens on cells of a variant human lymphoblastoid line.
EB4 lymphoblastoid cell line cells were cultured for 32 days with a ricin A chain-conjugated monoclonal antibody (McAb) to a beta chain determinant present on DP and DR antigens. A single colony of cells which survived this treatment was grown up and surface expression of MHC class II and B cell antigens measured. All class II antigens (DQ as well as DP and DR, alpha as well as beta chains) were initially greatly diminished, but substantial recovery of expression occurred within 20-100 days of culture (approx. 21-105 generations), although recovery was still incomplete. The CD19 (p95) B cell antigen was present in greater amount and the CD22 B cell antigen and surface immunoglobulin in lower amount on the variant line cells. It was confirmed that unconjugated anti-class II McAb binds to surface antigens but is unable to induce modulation even over an 8-day culture period. Evidence is presented that the gradual re-expression of class II antigens on the variant line cells is not due to the appearance of a mutant or to recovery from modulation. It is suggested that the variant line cells produce an excess of a regulatory molecule when grown in the conjugate.
D000911:Antibodies, Monoclonal / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology; D002460:Cell Line; D014644:Genetic Variation; D006682:HLA-DP Antigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000276:immunology; D006801:Humans; D008214:Lymphocytes / Q000276:immunology*; D012276:Ricin / Q000276:immunology
D000911:Antibodies, Monoclonal; D006682:HLA-DP Antigens; D006683:HLA-DQ Antigens; D006684:HLA-DR Antigens; D000949:Histocompatibility Antigens Class II; D012276:Ricin