title: Costimulatory receptors in jawed vertebrates: conserved CD28, odd CTLA4 and multiple BTLAs.
abstract: CD28 family of costimulatory receptors is comprised of molecules with a single V-type extracellular Ig domain, a transmembrane and an intracytoplasmic region with signaling motifs. CD28 and cytotoxic T lymphocyte antigen-4 (CTLA4) homologs have been recently identified in rainbow trout. Other sequences similar to mammalian CD28 family members have now been identified using teleost, Xenopus and chicken databases. CD28- and CTLA4 homologs were found in all vertebrate classes whereas inducible costimulatory signal (ICOS) was restricted to tetrapods, and programmed cell death-1 (PD1) was limited to mammals and chicken. Multiple B and T Lymphocyte Attenuator (BTLA) sequences were found in teleosts, but not in Xenopus or in avian genomes. The intron/exon structure of btlas was different from that of cd28 and other members of the family. The Ig domain encoded in all the btla genes has features of the C-type structure, which suggests that BTLA does not belong to the CD28 family. The genomic localization of these genes in vertebrate genomes supports the split between the BTLA and CD28 families.
authors.affiliation: Institut National de la Recherche Agronomique, Unité de Virologie et Immunologie Moléculaires, 78352 Jouy-en-Josas cedex, France.
authors.forename: David
authors.initials: D
authors.lastname: Bernard
authors.forename: John D
authors.initials: JD
authors.lastname: Hansen
authors.forename: Louis
authors.initials: L
authors.lastname: Du Pasquier
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Lefranc
authors.forename: Abdenour
authors.initials: A
authors.lastname: Benmansour
authors.forename: Pierre
authors.initials: P
authors.lastname: Boudinot
mesh_terms: D020816:Amino Acid Motifs / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000235:genetics*; D000943:Antigens, Differentiation / Q000235:genetics*; D018106:CD28 Antigens / Q000235:genetics*; D060908:CTLA-4 Antigen; D002645:Chickens / Q000235:genetics / Q000276:immunology; D030562:Databases, Protein; D005399:Fishes / Q000235:genetics* / Q000276:immunology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011971:Receptors, Immunologic / Q000235:genetics*; D016415:Sequence Alignment; D013601:T-Lymphocytes / Q000276:immunology; D014981:Xenopus / Q000235:genetics / Q000276:immunology
chemical_list: D015703:Antigens, CD; D000943:Antigens, Differentiation; C482586:BTLA protein, human; D018106:CD28 Antigens; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D011971:Receptors, Immunologic