High impact information on CD5

• 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 [1].
• The chicken CD5 is a 64-kDa phosphorylated glycoprotein with a protein core of 57 kDa as determined by immunoprecipitation and SDS-PAGE analysis [1].
• In contrast to human and mouse, CD5 is found at low levels on all chicken B cells [1].
• The high conservation of structural features, as well as signaling motifs, implies a conserved role for CD5 both in lymphocyte development and function [1].
• The chicken CD5 cDNA was isolated by COS cell expression cloning utilizing a novel mAb 2-191 [1].

Biological context of CD5

• 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 [1].
• There are 10 exons and the introns are spliced out similarly to those in the human CD5 gene [2].
• These results indicate that (a) mAb CTLA5 and 8 identify antigens on mature T lymphocytes that are similar in tissue distribution, molecular mass and function to the mammalian CD5 antigen; (b) mAb CTLA3, 4 and 9 detect the avian homologue of CD8 antigen; and (c) mAb CTLA1 and 6 identify the avian homologue of CD4 antigen [3].
• After polyclonal activation, the frequency of CD28+ gammadelta T cells was increased and the activation also up-regulated CD5, CD25 and major histocompatibility complex (MHC) class II molecules [4].

References