Cloning and comparison of bighorn sheep CD18 with that of domestic sheep, goats, cattle, humans and mice

• Published in: Veterinary Immunology and Immunopathology 2006-03, Vol.110 (1), p.11-16
• Main Authors: Liu, Weiguo, Brayton, Kelly A., Lagerquist, John, Foreyt, William J., Srikumaran, Subramaniam
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; amino acid sequences; Animals; Base Sequence; Bighorn sheep; Cattle; CD18; CD18 Antigens - genetics; CD18 Antigens - immunology; cDNA; Cloning; Cloning, Molecular; Cluster Analysis; complementary DNA; Conserved Sequence; Goats; Humans; integrins; leukocytes; leukotoxins; Mannheimia haemolytica; Mice; Molecular Sequence Data; monocytes; neutrophils; nucleotide sequences; Open Reading Frames; Ovis canadensis; Pasteurella haemolytica; protein subunits; receptors; Reverse Transcriptase Polymerase Chain Reaction - veterinary; RNA - chemistry; RNA - genetics; Ruminantia; Sequence Alignment; sequence analysis; Sequence Homology, Amino Acid; Sequencing; sheep; Sheep - genetics; Sheep - immunology; Species Specificity; wild animals
• ISSN: 0165-2427; 1873-2534; 1365-2567
• DOI: 10.1016/j.vetimm.2005.08.030

Previously, we have shown that CD18, the β-subunit of β 2-integrins, serves as a receptor for leukotoxin (Lkt) secreted by Mannheimia ( Pasteurella) haemolytica on bovine leukocytes. Anti-CD18 monoclonal antibodies (mAbs) inhibit Lkt-induced cytolysis of bighorn sheep ( Ovis canadensis) leukocytes suggesting that CD18 may serve as a receptor for Lkt on the leukocytes of this species as well. Confirmation of bighorn sheep CD18 as a receptor for Lkt, and elucidation of the enhanced Lkt-susceptibility of bighorn sheep polymorphonuclear leukocytes (PMNs), necessitates the cloning and sequencing of cDNA encoding bighorn sheep CD18. Hence, in this study we cloned and sequenced the cDNA encoding CD18 of bighorn sheep, and compared with that of other animal species. The cDNA of bighorn sheep CD18 has an open reading frame (ORF) of 2310 bp. CD18 sequences obtained individually from peripheral blood mononuclear cells (PBMCs) and PMNs were identical to each other. Comparison of the deduced 770-amino acid sequence of CD18 of bighorn sheep with that of domestic sheep, goats, cattle, humans and mice revealed 99, 98, 95, 82 and 80% identity, respectively. Availability of cloned bighorn sheep CD18 cDNA should allow the molecular characterization of M. haemolytica Lkt–receptor interactions in bighorn sheep and other ruminants that are susceptible to this disease.