title: Purification, chain separation and sequence of the MRC OX-8 antigen, a marker of rat cytotoxic T lymphocytes.
abstract: The MRC OX-8 antigen is a marker of the rat cytotoxic T lymphocytes that consists of disulphide-linked chains of mol. wts. 37 and 32 kd. It is thought to be equivalent to the human T8 and mouse Lyt2,3 antigens (all now called CD8 antigens). MRC OX-8 antigen was purified from thymocytes using a monoclonal antibody column and because antigenicity was retained after reduction and alkylation the two polypeptide chains could be separated by a subsequent affinity chromatography step. Peptides were isolated from each chain and their sequences determined. A cDNA probe coding for the mouse CD8 antigen (pLY2C-1 provided by Dr L. A. Herzenberg) was used to obtain rat cDNA clones from which the sequence of the equivalent rat molecule was determined. Peptides from the 32-kd chain were identified in this translated sequence whereas peptides from the 37-kd chain were not. The 32-kd polypeptide sequence consisted of 210 amino acids and had one possible N-linked glycosylation site. The N-terminal part of the sequence was surprisingly different from both its mouse and human counterparts but, as in the other two species, it showed a clear relationship to Ig V domains.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000235:genetics / Q000302:isolation & purification*; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D008970:Molecular Weight; D021382:Protein Sorting Signals; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D013602:T-Lymphocytes, Cytotoxic / Q000032:analysis*
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D046911:Macromolecular Substances; D008565:Membrane Proteins; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D004247:DNA