Ly-1 B cells: functionally distinct lymphocytes that secrete IgM autoantibodies.
Studies presented here introduce another perspective on the mechanisms responsible for IgM autoantibody production. A unique subpopulation of B lymphocytes (Ly-1 B) that concomitantly expresses IgM, IgD, Ia, and Ly-1 membrane glycoproteins is present at higher frequencies in NZB and NZB-related mice. The Ly-1 B subpopulation in these autoimmune animals is responsible for the "spontaneous" IgM secretion demonstrated with cultured NZB spleen cells and contains the cells that secrete typical NZB IgM autoantibodies to single-stranded DNA and to thymocytes. In addition, the Ly-1 B population in normal mouse strains (and in NZB) contains virtually all of the spleen cells that secrete IgM autoantibodies reactive with bromelain-treated mouse erythrocytes. Since a different B-cell subpopulation (IgM+, IgD-, Ly-1) secretes most of the IgM antibodies produced in responses to exogenous antigens, we conclude that Ly-1 B cells constitute a functionally distinct B-cell population important in certain kinds of autoimmunity.
D000818:Animals; D000936:Antigen-Antibody Complex; D001323:Autoantibodies / Q000502:physiology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D005434:Flow Cytometry; D007075:Immunoglobulin M / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains; D013045:Species Specificity
D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D007075:Immunoglobulin M