The structure of avian CD5 implies a conserved function.
The chicken CD5 cDNA was isolated by COS cell expression cloning utilizing a novel mAb 2-191. The cDNA contains a 1422-nucleotide open reading frame encoding a mature protein with 32% and 30% identity to mouse and human CD5 polypeptides, respectively. The molecule consists of a 330-amino acid extracellular region with three repeats of the scavenger receptor cysteine-rich domain, a 29-amino acid hydrophobic transmembrane domain, and a 93-amino acid cytoplasmic tail. The cytoplasmic region contains motifs that are highly conserved between species, including several potential phosphorylation sites. The chicken CD5 is a 64-kDa phosphorylated glycoprotein with a protein core of 57 kDa as determined by immunoprecipitation and SDS-PAGE analysis. Alphabeta T cells express a homogeneously high level of CD5, whereas low or intermediate CD5 expression on gammadelta T cells depends on their tissue location. In contrast to human and mouse, CD5 is found at low levels on all chicken B cells. The high conservation of structural features, as well as signaling motifs, implies a conserved role for CD5 both in lymphocyte development and function.
Koskinen
R
R
Turku Immunology Centre and Department of Medical Microbiology, Turku University, Finland.
Göbel
T W
TW
Tregaskes
C A
CA
Young
J R
JR
Vainio
O
O
D000595:Amino Acid Sequence; D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D018956:CD5 Antigens / Q000737:chemistry* / Q000502:physiology; D002645:Chickens / Q000276:immunology*; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data
D018956:CD5 Antigens