Mannheimia haemolytica is an important cause of pneumonia in bighorn sheep (BHS; Ovis canadensis). Leukotoxin (Lkt), the primary virulence determinant of M. haemolytica, induces cytolysis of all subsets of leukocytes. Previously, we have shown that CD18, the beta subunit of beta2-integrins, mediates Lkt-induced cytolysis. However, it is not clear whether CD18 of all three beta2-integrins, LFA-1, Mac-1, and CR4, mediates Lkt-induced cytolysis. The objective of this study was to determine whether BHS LFA-1 (CD11a/CD18) serves as a receptor for Lkt. Plasmids encoding cDNA for BHS CD11a and CD18 were cotransfected into Lkt-resistant HEK-293 cells. Flow cytometric analysis of transfectants confirmed cell surface expression of BHS LFA- 1, Lkt-LFA-1 binding and Lkt-induced intra-cellular calcium elevation. More importantly, the transfectants were efficiently lysed by Lkt in a concentration-dependent manner. Collectively, these results indicate that BHS LFA-1 serves as a functional receptor for M. haemolytica Lkt.
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http://dx.doi.org/10.7589/0090-3558-44.3.743 | DOI Listing |
Microorganisms
December 2024
Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA 99164, USA.
Bighorn sheep (BHS) populations have been reported to experience high levels of morbidity and mortality following infection with . This contrasts with the subclinical presentation in domestic sheep (DS). Understanding this difference requires baseline knowledge of pre- and post-infection immune responses of both species.
View Article and Find Full Text PDFSci Rep
December 2024
United States Fish and Wildlife Service, Tulsa, OK, USA.
Abundance estimates inform ungulate management and recovery efforts. Yet effective and affordable estimation techniques remain absent for most ungulates lacking identifiable marks and inhabiting rugged or highly vegetated terrain. Methods using N-mixture models with camera trap imagery form an appealing solution but remain unvalidated.
View Article and Find Full Text PDFAbstractDensity dependence is often assumed in population dynamics, but its importance in small, isolated populations has been questioned. We evaluated the relative influence of density dependence, environmental conditions, and sporadic events (disease outbreaks and specialist predators) on annual population growth rate, annual female reproduction, and annual survival of juveniles and adult females in three populations of mountain ungulates. We analyzed long-term (30-47 years) individual-based data on two bighorn sheep populations and one mountain goat population in Alberta, Canada.
View Article and Find Full Text PDFJ Wildl Dis
November 2024
Southeastern Cooperative Wildlife Disease Study, 589 D. W. Brooks Dr., Athens, Georgia 30602, USA.
Mol Biol Evol
November 2024
Frontiers Science Center for Molecular Design Breeding (MOE), State Key Laboratory of Animal Biotech Breeding, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Previous studies revealed extensive genetic introgression between Ovis species, which affects genetic adaptation and morphological traits. However, the exact evolutionary scenarios underlying the hybridization between sheep and allopatric wild relatives remain unknown. To address this problem, we here integrate the reference genomes of several ovine and caprine species: domestic sheep, argali, bighorn sheep, snow sheep, and domestic goats.
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