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  Home > VBS Faculty > Samuel Maheswaran

Samuel Maheswaran

Dr. Sam Maheswaran



e-mail: mahes001@umn.edu

205 Veterinary Science Building
1971 Commonwealth Avenue
University of Minnesota

St. Paul, MN 55108


B.V.Sc., University of Ceylon
M.S., University of Minnesota
Ph.D., University of Minnesota
Post-Doctoral Research Trainee, School of Medicine, University of Manitoba, Canada

Research Interests 
Molecular mechanisms of lung damage in bovine pneumonic mannheimiosis; Cytokine biology; Virulent factors and biology of Actinobacillus pleuropneumoniae infections in swine; Identification and characterization of the virulent gene(s) of avian Pasteurella multocida; Biology of RTX cytolysins. The primary research interest of my laboratory is studying the precise molecular and cellular mechanisms involved in the pathogenesis of pneumonia caused by Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, and Actinobacillus pleuropneumonia. Under this broad heading there are two major projects with  biology of  Mannheimia haemolytica leukotoxin, and signaling cascades being unifying themes:

Bovine pneumonic mannheimiosis—studies are designed to characterize the molecular basis of M.haemolytica leukotoxin interaction with the beta 2 integrin receptor on bovine leukocytes and delineate the post receptor signaling pathways that lead to production of inflammatory mediators resulting in pneumonia.

Bovine pneumonic mannheimiosis — focus on precise mapping of the leukotoxin binding site within the CD18 subunit of bovine beta 2 integrins. Once this is accomplished, we will design small molecule inhibitors or peptidomimetics capable of preventing leukotoxin binding and the ensuing signaling leading to leukocyte activation and inflammatory response in the bovine lung.

Selected Publications 
(For a comprehensive list of  Dr. Maheswaran's recent publications, refer to PubMed, a service provided by the National Library of Medicine.)

Jeyaseelan, S., Hsuan, S.L., Kannan, M.S., Walcheck, B., Wang, J.F., Kehrli, M.E., Lally, E.T., Sieck, G.C., Maheswaran, S.K. 2000. Lymphocyte function-associated antigen-1 is a receptor for Pasteurella haemolytica leukotoxin in bovine leukocytes. Infect. Immun. 68: 72-79.

Jeyaseelan, S., Kannan, M.S., Hsuan, S.L., Singh, A.K., Walseth, T.F., Maheswaran, S.K. 2001. Pasteurella haemolytica leukotoxin-induced cytolysis of bovine leukocytes: Role of arachidonic acid and its regulation. Microb. Pathog. 30: 59-69.

Jeyaseelan, S., Kannan, M.S., Briggs, R.E., Thumbikat, P., Maheswaran, S.K. 2001. Mannheimia haemolytica leukotoxin activates a non-receptor tyrosine kinase signaling cascade in bovine leukocytes which induces biological activity. Infect. Immun. 69: 6131-6139.

Jeyaseelan, S., and Maheswaran, S.K. 2003. Recent advances in the pathobiology of shipping fever pneumonia. Invited Review. Veterinary Quarterly-Reviews on Animal Diseases. 25: 151-173.

Malazdrewich, C., P. Thumbikat, M.S. Abrahamsen, and S.K. Maheswaran. 2004. Pharmacological inhibition of Mannheimia haemolytica lipopolysaccharide and leukotoxin-induced cytokine expression in bovine alveolar macrophages.  Microb. Pathog.  36: 159-169.

Malazdrewich, C.,  P. Thumbikat, and S.K. Maheswaran. 2004. Protective effect of dexamethasone in experimental bovine pneumonic mannheimiosis. Microb. Pathog. 36: 227-237.

Thumbikat, P., T. Dileepan, M.S. Kannan, and S.K. Maheswaran. 2005. Mechanisms underlying Mannheimia haemolytica leukotoxin-induced oncosis and apoptosis of bovine leukocytes. Microb. Pathog.  38: 161-172.

Dileepan, T., P. Thumbikat, B. Walcheck, M.S. Kannan, and S.K. Maheswaran. 2005. Recombinant expression of bovine LFA-1 and characterization of its role as the receptor for Mannheimia haemolytica leukotoxin.  Microb. Pathog.  38: 249-257.

Thumbikat, P., T. Dileepan, M.S. Kannan, and S.K. Maheswaran. 2005. Characterization of Mannheimia (Pasteurella) haemolytica leukotoxin interaction with bovine alveolar macrophage beta2 integrins. Veterinary Research.  36: 771-786.

Dileepan, T., M.S. Kannan, B. Walcheck, P. Thumbikat, and S.K. Maheswaran. 2005. Mapping of the binding site for Mannheimia haemolytica leukotoxin within the bovine CD18. Infection and Immunity. 73: 5233-5237.

Abrahante, J.E., T. J. Johnson, S.S. Hunter, S.K. Maheswaran, and R.E. Briggs. 2013. Draft Genome sequences of two virulent serotypes of avian Pasteurella multocida. Genome Announcement. January/February2013 1:e00058-12; doi:10 1128/genomeA. 00058-12.

Johnson, T.J., J.E. Abrahante, S. S. Hunter, M. Hauglund, F. M. Tatum, S. K. Maheswaran, and R.E. Briggs. 2013. Comparative genome analysis of an avirulent and two virulent strains of avian Pasteurella multocida reveals candidate genes involved in fitness and pathogenicity. BMC Genomics. 2013, 13:106. doi: 10.1186/147-2180-13-106.

Briggs, R.E., S. K. Maheswaran, M. J. Hauglund, and F.E. Tatum. 2013. Bivalent vaccination against pneumonic pasteurellosis in domestic sheep and goats with modified-live in-frame lktA deletion mutants of Mannheimia haemolytica. Microb. Pathog. 64: 43-47.

Hauglund, M.J., F.M. Tatum, D.O. Bayles, S.K. Maheswaran, and R.E. Briggs. 2013. Genome sequences of Mannheimia haemolytica serotype A1 strains D153 and D193 from bovine pneumonia. Genome Announc. September/October 2013 1:e00848-13; doi: 10.1128/genomeA 00848-13.

Abrahante, J. E, B. M. Veeregowda, S. Hogtapur, R. E. Briggs, S. K. Maheswaran, and S. Sreevatsan. 2014. Draft genome sequences of two Pasteurella multocida strains isolated from Buffaloes in India with hemorrhagic septicemia disease. Genome Announc. 2(4):e00798-14.doi:10.1128/genomeA.00798-14.

Hauglund, M., F. M. Tatum, D.O. Bayles, S. K. Maheswaran, and R. E. Briggs. 2015. Genome sequences of serotype A6 Mannheimia haemolytica isolates D174 and D38 recovered from bovine pneumonia. Genome Announc. 3(2):e00086-15.doi:10.1128/genomea.00086-15.

Hauglund, M., F. M. Tatum, D.O. Bayles, S. K. Maheswaran, and R. E. Briggs. 2015. Genome sequences of serotype A2 Mannheimia haemolytica isolates D171 and D35 recovered from bovine pneumonia. Genome Announc. 3(2):e00093-15.doi:10.1128/genomea.00093-15.

Current Funding 
"Characterization of Pasteurella haemolytica leukotoxin-receptor interaction in bovine leukocytes," Minnesota Agricultural Experiment Station.

Honors and Awards 
Pfizer Animal Health Award for Research Excellence, College of Veterinary Medicine. 1995.

Excellence in Graduate Teaching and Research, Department of Veterinary PathoBiology. 1995.

Current Students 
T. Dileepan, Ph.D. student



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