Molecular cloning and characterisation of the CD18 partner in ovine (Ovis aries) β2-integrins

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 ovine β2 (CD18) subunit, common to the leukocyte β2-integrin family. The deduced 770-amino-acid sequence reveals a transmembrane protein with 81%, 83% and 95% identity with its murine, human and bovine homologues, respectively. Comparisons of CD18 sequences emphasize the functional importance of the β2 subunit I-like domain and included metal ion-dependent adhesion site (MIDAS)-like motif and confirm that of the cytoplasmic tail. The data provided here will offer the possibility to explore new avenues in studies based on the ovine model.