On the function of Ly-5 in the regulation of antigen-driven B cell differentiation. Comparison and contrast with Lyb-2.
Generation of anti-sheep erythrocyte plaque-forming cells (PFC) is greatly reduced in the presence of monoclonal Ly-5 alloantibody. Although Ly-5 is expressed in one of its molecular forms on T cells and macrophages (M phi ) involved in this response, the only demonstrated action of Ly-5 antibody was on B cells. Evidence from elimination of Lyt-2+ cells, and from the responses of serial proportions of Ly-5.1 and Ly-5.2 cells and of Ly-5 heterozygous cells, signifies that PFC reduction cannot be ascribed to any known mechanism of suppression or to a direct suppressive action of Ly-5 antibody on B cells. A critical distinction of Ly-5 from Lyb-2 is that Ly-5 antibody reduces PFC generation to trinitrophenylated Ficoll, a thymus-independent type 2 antigen requiring T cells and M phi for maximal PFC generation in vitro. A second distinction is that PFC reduction by Ly-5 antibody is strictly tied to the time of operation of M phi factor, whereas PFC reduction by Lyb-2 antibody relates to the time of B cell triggering by antigen. Accordingly, M phi factor competitively and quantitatively inhibits the action of Ly-5 antibody in reducing PFC generation. It is likely that the Ly-5 system is concerned in the reception or handling of M phi message by B cells.
D000818:Animals; D000921:Antibody-Producing Cells / Q000166:cytology / Q000276:immunology; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface / Q000145:classification / Q000235:genetics / Q000276:immunology*; D000955:Antigens, T-Independent / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D006462:Hemolytic Plaque Technique; D007108:Immune Tolerance; D007518:Isoantibodies / Q000502:physiology; D007700:Kinetics; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000276:immunology
D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D000955:Antigens, T-Independent; D007518:Isoantibodies