title: The "Ly-1 B" cell subpopulation in normal immunodefective, and autoimmune mice.
abstract: A small subpopulation of normal murine splenic B cells carrying all of the classic B cells markers (IgM, IgD, Ia, and ThB) also carries Ly-1, one of the major T cell surface molecules. This "Ly-1 B" subpopulation (identified and characterized by multiparameter FACS analyses) consists of relatively large, high IgM/low-IgD/low-Ly-1 lymphocytes that represent approximately 2% of the spleen cells in normal animals and, generally, 5-10% of spleen cells in NZB mice. Ly-1 B are clearly detectable in all normal mouse strains tested as well as NZB, CBA/N, other X-id mice and nude (nu/nu) mice. They are found primarily in the spleen; are either absent or very poorly represented in lymph node, bone marrow, and thymus; appear early during ontogeny, and comprise about a third of the small number of lymphocytes present in 5-d-old mice. NZB and (NZB x NZW)F1 mice have more Ly-1 B than all other strains and, furthermore, have a unique Ly-1 B population that secretes IgM when cultured under usual conditions in the absence of added antigen. The IgM secretion by these Ly-1 B cells accounts for the previously reported "spontaneous" IgM secretion by NZB spleen cells in culture. Studies with FACS-sorted cells show that the presence of Ly-1 on these IgM-secreting cells distinguishes them from the (Ly-1 negative) IgM-secreting "direct" plaque-forming cells generated in NZB mice after stimulation with sheep erythrocytes.
mesh_terms: D000367:Age Factors; D000818:Animals; D000950:Antigens, Ly / Q000032:analysis*; D000954:Antigens, Surface / Q000032:analysis; D001327:Autoimmune Diseases / Q000276:immunology*; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology*; D002469:Cell Separation; D005434:Flow Cytometry; D007075:Immunoglobulin M / Q000032:analysis; D007153:Immunologic Deficiency Syndromes / Q000276:immunology*; D051379:Mice; D008814:Mice, Inbred NZB / Q000276:immunology; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D013154:Spleen / Q000166:cytology / Q000196:embryology
chemical_list: D000950:Antigens, Ly; D000954:Antigens, Surface; D007075:Immunoglobulin M; D011947:Receptors, Antigen, B-Cell