title: Further definition of the Ly-5 system.
abstract: Ly-5 is expressed by cells of the hematopoietic branch of development. Further serological analysis of the Ly-5 system, aided by Ly-5 monoclonal antibodies and by two Ly-5 congenic mouse strains, reveals two new Ly-5 alloantigens, Ly-5.3 and Ly-5.4. The data define three thymocyte phenotypes, Ly-5.1,3, Ly-5.2,4, and Ly-5.2,3, and three corresponding genotypes, Ly-5a, Ly-5b, and Ly-5c, respectively. Ly-5a is by far the most common allele. The Ly-5c allele is found only in the ST/bJ strain, a finding that accords with the presently unique pattern of restriction fragments previously observed in Southern blotting of ST/bJ DNA with an Ly-5 cDNA probe. Present serological and biochemical data favor the interpretation that the compound Ly-5 phenotype of thymocytes is attributable to two separate Ly-5 molecular isoforms that exhibit a discrete difference in protein composition, bear different Ly-5 antigens, and are produced jointly by thymocytes, unlike other Ly-5 isoforms previously shown to distinguish different hematopoietic cell lineages.
mesh_terms: D000483:Alleles; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000950:Antigens, Ly / Q000235:genetics / Q000276:immunology*; D002454:Cell Differentiation; D006412:Hematopoietic Stem Cells / Q000276:immunology; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000950:Antigens, Ly