title: Similarities in sequences and cellular expression between rat CD2 and CD4 antigens.
abstract: The MRC OX-34 antigen of rat T lymphocytes was purified and peptide sequences were obtained. Oligonucleotide probes were synthesized and cDNA clones coding for the antigen were isolated and sequenced to yield a predicted protein sequence for the molecule that fitted the peptide data. Comparison of this sequence with that for human CD2 determined by Sewell et al. showed that OX-34 is rat CD2. The primary structure of the molecule was notable for a moderately large cytoplasmic domain of unusual sequence and also for its highly significant relationship to CD4 antigen in the membrane proximal extracellular region and the transmembrane sequence. A relationship to the Ig superfamily can be argued for the two extra cellular domains of CD2, even though neither fits the standard pattern for Ig-related domains. Within the T lymphocyte lineage, rat CD2 seemed to be present on all stages with the exception of approximately 50% of the thymic CD4-,CD8- cells. In addition, the antigen was prominent on most macrophages in the spleen but not found on peritoneal or liver macrophages. CD4 antigen is also expressed on T lymphocytes and macrophages, and thus CD2 and CD4 appear similar in their cellular expression as well as structural characteristics.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology* / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology; D008264:Macrophages / Q000276:immunology; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D004247:DNA