Subramaniam (Sri) Srikumaran
Professor
Rocky Crate-Foundation for North American Wild Sheep Endowed Chair
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
-
Identification of CD18 peptide analogs that inhibit leukotoxin binding
to leukocytes;
-
Elucidation of the role of the
α
subunits of
β2-integrins in
leukotoxin binding of CD18;
-
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.
