title: Expression of an avian CD6 candidate is restricted to alpha beta T cells, splenic CD8+ gamma delta T cells and embryonic natural killer cells.
abstract: A candidate avian CD6 homolog is identified by the S3 monoclonal antibody. The S3 antigen exists in a phosphorylated glycoprotein form of 130 kDa and a nonphosphorylated form of 110 kDa. Removal of phosphate groups and N-linked carbohydrates indicates a 78-kDa protein core. During thymocyte differentiation, the gamma delta T cells do not express S3, whereas mature CD4+ and CD8+ cells of alpha beta lineage acquire S3 antigen. All alpha beta T cells in the blood and spleen express the S3 antigen at relatively high levels. In contrast, only the CD8+ subpopulation of gamma delta T cells in the spleen expresses the antigen and neither alpha beta nor gamma delta T cells in the intestinal epithelium express the S3 antigen. The S3 antigen is also found on embryonic splenocytes with a phenotypic profile characteristic of avian natural killer cells. The biochemical characteristics and this cellular expression pattern imply that the S3 antigen is the chicken CD6 homolog.
authors.affiliation: Basel Institute for Immunology, Switzerland. goebel@bii.ch
authors.forename: T W
authors.initials: TW
authors.lastname: Göbel
authors.forename: C H
authors.initials: CH
authors.lastname: Chen
authors.forename: M D
authors.initials: MD
authors.lastname: Cooper
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry; D015703:Antigens, CD / Q000096:biosynthesis* / Q000737:chemistry; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000737:chemistry; D018414:CD8-Positive T-Lymphocytes / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D002642:Chick Embryo; D002645:Chickens; D007694:Killer Cells, Natural / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D009928:Organ Specificity / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology* / Q000378:metabolism; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology* / Q000378:metabolism; D013154:Spleen / Q000166:cytology* / Q000196:embryology
chemical_list: D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; C062279:CD6 antigen; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta