Shanthalingam Sudarvili, Norimine Junzo, Brown Wendy C, Srikumaran Subramaniam
Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA.
Vet Immunol Immunopathol. 2010 Jul;136(1-2):163-9. doi: 10.1016/j.vetimm.2010.01.006. Epub 2010 Feb 1.
Pneumonia caused by Mannheimia haemolytica is an important disease of cattle, domestic sheep, bighorn sheep and goats. Leukotoxin (Lkt) produced by M. haemolytica is cytolytic to all leukocyte subsets of these species. Lkt utilizes CD18, the beta subunit of beta(2)-integrins, as its functional receptor on leukocytes of these species. Cytotoxicity assays revealed that leukocytes from bison, deer, and elk are also susceptible to Lkt-induced cytolysis. The availability of cDNA encoding CD18 of bison, deer and elk would facilitate the comparison of a greater number of ruminant CD18 cDNA with that of non-ruminants as a means of the elucidation of the molecular basis for the specificity of M. haemolytica Lkt for ruminant leukocytes. Herein, we report the cloning and characterization of bison, deer, and elk CD18. The full-length cDNA of bison and deer consists of 2310bp with an ORF encoding 769 amino acids while elk CD18 consists of 2313bp with an ORF encoding 770 amino acids. This gene is highly conserved among ruminants compared with non-ruminants. Phylogenetic analysis based on amino acid sequences showed that CD18 of bison is most closely related to that of cattle while CD18 of deer and elk are more closely related to each other.
溶血曼氏杆菌引起的肺炎是牛、家羊、大角羊和山羊的一种重要疾病。溶血曼氏杆菌产生的白细胞毒素（Lkt）对这些物种的所有白细胞亚群具有细胞溶解作用。Lkt利用β₂整合素的β亚基CD18作为这些物种白细胞上的功能受体。细胞毒性试验表明，野牛、鹿和麋鹿的白细胞也易受Lkt诱导的细胞溶解作用影响。编码野牛、鹿和麋鹿CD18的cDNA的可用性将有助于将更多反刍动物的CD18 cDNA与非反刍动物的进行比较，以此阐明溶血曼氏杆菌Lkt对反刍动物白细胞特异性的分子基础。在此，我们报告了野牛、鹿和麋鹿CD18的克隆与特性。野牛和鹿的全长cDNA由2310bp组成，开放阅读框编码769个氨基酸，而麋鹿CD18由2313bp组成，开放阅读框编码770个氨基酸。与非反刍动物相比，该基因在反刍动物中高度保守。基于氨基酸序列的系统发育分析表明，野牛的CD18与牛的最为密切相关，而鹿和麋鹿的CD18彼此之间关系更为密切。
