title: Molecular cloning and expression of feline CD28 and CTLA-4 cDNA.
abstract: Feline CD28 and CTLA-4 (CD152) cDNA were cloned from Con-A stimulated feline peripheral blood mononuclear cells (PBMC) by rapid amplification of cDNA end-PCR (RACE-PCR). Both CD28 and CTLA-4 proteins belong to the immunoglobulin superfamily (Ig SF) and are composed of a signal sequence, an extracellular domain, a transmembrane domain and a cytoplasmic domain. The open reading frame (ORF) of CD28 cDNA encoded a predicted protein of 221 amino acids and that of CTLA-4 cDNA encoded a predicted protein of 223 amino acids. The B7 ligands binding motif MYPPPY hexamer was found on the extracellular Ig V-like domains of both receptors and phosphatidylinositol 3-kinase (PI 3-kinase) binding motifs pYMNM for CD28 and pYVKM for CTLA-4 were identified in the cytoplasmic domains. Comparisons of amino acid sequences of feline proteins with known sequences of other species indicated that rabbit CD28 and CTLA-4 were most closely related and mouse molecules were the least conserved with feline molecules. Comparison of each domain of both molecules with that of other animals showed that the cytoplasmic domain of CTLA-4 was 100% conserved and that of CD28 was the most conserved domain. The cloned CD28 and CTLA-4 cDNA could be expressed in transfected mammalian cells. Expression of feline CD28 and CTLA-4 mRNA in freshly isolated feline PBMC was demonstrated by RT-PCR. Stimulation of PBMC with Con-A similarly increased the expression of both CD28 and CTLA-4 mRNA.
authors.affiliation: Department of Veterinary Pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX 77843-4467, USA.
authors.forename: I S
authors.initials: IS
authors.lastname: Choi
authors.forename: S M
authors.initials: SM
authors.lastname: Hash
authors.forename: E W
authors.initials: EW
authors.lastname: Collisson
mesh_terms: D000069594:Abatacept; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D000943:Antigens, Differentiation / Q000096:biosynthesis* / Q000235:genetics*; D018106:CD28 Antigens / Q000096:biosynthesis* / Q000235:genetics*; D060908:CTLA-4 Antigen; D002415:Cats; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D006801:Humans; D018796:Immunoconjugates; D007141:Immunoglobulin Fc Fragments / Q000096:biosynthesis / Q000235:genetics; D007166:Immunosuppressive Agents; D051379:Mice; D008969:Molecular Sequence Data; D011817:Rabbits; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D016415:Sequence Alignment; D013047:Specific Pathogen-Free Organisms; D014162:Transfection / Q000662:veterinary
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; D018106:CD28 Antigens; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; C556707:Ctla4 protein, mouse; D018076:DNA, Complementary; D018796:Immunoconjugates; D007141:Immunoglobulin Fc Fragments; D007166:Immunosuppressive Agents; D011993:Recombinant Fusion Proteins; D000069594:Abatacept