title: The lipoprotein of the outer membrane of Escherichia coli: a B-lymphocyte mitogen.
abstract: The lipoprotein of the outer membrane of Escherichia coli is a B-cell mitogen in mice.  Polyclonal activation of B lymphocytes was measured by an increase in thymidine uptake, by the development of plaque-forming cells against densely coupled trinitrophenylated sheep red cells, and by selectively increased rates of synthesis and secretion of leucine-labeled IgM. Murein-free and muropeptides-containing lipoprotein are effective in B-cell activation, while free murein is inactive.  Removal of ester-linked fatty acids from the amino-terminal end of the lipoprotein by alkaline hydrolysis abolishes the mitogenicity of the lipoprotein. B lymphocytes from high responder (C3H/Tif and BALB/c nu/nu) or from low responder (C3H/HeJ) mice to the mitogen lipopolysaccharide (LPS) both respond well to the lipoprotein.  Anti-immunoglobulin antibodies inhibit the mitogenic stimulation of B cells by lipoprotein.  A complex of structures including the Ig-receptor molecules, the LPS receptor, and the lipoprotein receptor appear involved in the regulation of mitogenic stimulation of B cells to proliferation and differentiation to IgM-secreting cells.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic; D001402:B-Lymphocytes / Q000502:physiology*; D002455:Cell Division; D002462:Cell Membrane; D004926:Escherichia coli; D006462:Hemolytic Plaque Technique; D007075:Immunoglobulin M / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008074:Lipoproteins; D051379:Mice; D008809:Mice, Inbred C3H; D008934:Mitogens; D010457:Peptidoglycan / Q000502:physiology; D013154:Spleen / Q000166:cytology; D013936:Thymidine / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology; D014316:Tritium
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007075:Immunoglobulin M; D008074:Lipoproteins; D008934:Mitogens; D010457:Peptidoglycan; D014316:Tritium; D007930:Leucine; D013936:Thymidine