College of Veterinary Medicine

Veterinary Microbiology and Pathology

Subramaniam (Sri) Srikumaran 


Professor
Rocky Crate D.V.M. and Wild Sheep Foundation Endowed Chair in Wild Sheep Disease Research
ssrikumaran@vetmed.wsu.edu
509-335-4572 (phone)
509-335-8529 (fax)

Education & Training


BVSc: University of Ceylon
MS: University of Maryland
PhD: University of Maryland
Post-doctoral: Amherst College, Massachusetts
Sabbatical: University of Oxford, U.K.

 

Research Interests

My research program is focused on diseases of wild sheep in general, and pneumonia in particular. The current focus is on understanding the pathogenesis of pneumonia caused by Mannheimia and Pasteurella species. Leukotoxin is the most important virulence factor of these organisms, and is cytolytic to all subsets of leukocytes. Research in my laboratory during the past few years has identified CD18, the β subunit of β2-integrins, as the receptor for leukotoxin on the leukocytes of bighorn sheep, domestic sheep, and cattle. More recent studies have mapped the leukotoxin binding site on the CD18 molecule.

Current research projects on leukotoxin and its receptor include

  1. Identification of CD18 peptide analogs that inhibit leukotoxin binding to leukocytes;
  2. Elucidation of the role of the α subunits of β2-integrins in leukotoxin binding of CD18;
  3. Analysis of the role of inflammatory cytokines IL-1-β and TNF-α in the expression of leukotoxin receptor, and pathogenesis of pneumonia.


Bighorn sheep are much more susceptible than domestic sheep to pneumonia caused by Mannheimia and Pasteurella species. Polymorphonuclear leukocytes (PMNs) of bighorn sheep are 8-16 fold more susceptible to leukotoxin than those of domestic sheep. Our working hypothesis is that bighorn sheep are more susceptible than domestic sheep to pneumonia because their PMNs are more susceptible to leukotoxin than those of domestic sheep. One facet of our research examines the molecular basis for the enhanced susceptibility of bighorn sheep PMNs. Another facet examines the role of other virulence factors in the pathogenesis of pneumonia. Yet another facet of our research examines the possible role of viral infections in pneumonia of bighorn sheep. The long term goal of my laboratory is to develop control measures against pneumonia which has decimated bighorn sheep populations time and time again in the past.

Publications

Last Edited: Jun 25, 2012 7:17 AM   

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