Cloning and expression of the chicken CD18 cDNA.

The leukocyte integrins play a critical role in a number of cellular adhesive interactions during the immune response. We describe here the isolation and characterization of the chicken beta 2 (CD18) subunit, common to the leukocyte integrin family. The deduced 748-amino-acid sequence reveals a transmembrane protein with 65% and 64% identity with its human and murine homologues, respectively. The chicken beta 2 can associate on the cell surface with the human alpha subunit of LFA-1 and yields a hybrid molecule capable of binding to purified ICAM-1 and ICAM-3.