Molecular identification of a surface structure on B cells (Lyb-3) and its relationship to B cell triggering.
Lactoperoxidase-catalyzed radioiodination of cell surface proteins and immunochemical procedures are used to identify murine splenic lymphocyte membrane components bound by anti-Lyb-3 serum. This antiserum defines membrane components (Lyb-3) on a subpopulation of murine B cells that may function as a receptor for T cell signals. SDS-PAGE analysis of surface-labeled membrane components bound by anti-Lyb-3 serum demonstrated a single molecular species of 68,000 d. The polypeptides recognized by anti-Lyb-3 are not composed of disulfide-linked subunits and bear no antigenic relationship with known membrane immunoglobulins (IgM or IgD). Absorption of anti-Lyb-3 serum with the 68,000 d polypeptides removed the ability of anti-Lyb-3 serum to augment the in vivo immune response of mice to low doses of sheep erythrocytes. The latter provides formal proof that the 68,000 d polypeptide bound by anti-Lyb-3 serum is the target on the B cell membrane for the immunoenhancing activity of the antiserum.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody; D002462:Cell Membrane / Q000276:immunology; D007106:Immune Sera / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008968:Molecular Conformation; D008970:Molecular Weight; D010455:Peptides / Q000302:isolation & purification; D013154:Spleen / Q000276:immunology
D007106:Immune Sera; D010455:Peptides