C-Reactive Protein and Interleukin 6: Establishment of New Techniques for the Early Detection of Inflammatory Disease in Marine Mammal Species
D.P. King; C. Funke; T.H. Reidarson; D.A. Ferrick; J.L. Stott
The International Program for Marine Mammal Health, Department of
Pathology, Microbiology and Immunology, University of California, Davis, CA; Sea World of
California, San Diego, CA
The ability to detect the presence of and quantify the inflammatory
response in marine mammal species would be diagnostically useful in captive, rehabilitation and
field situations. This report describes two assays currently under development to measure the
acute phase response in marine mammals using specific reagents generated for interleukin 6 (IL-6)
and C-reactive protein (C-RP).
IL-6, described in a number of mammalian species, is a multi-functional
soluble cytokine (hormone of the immune system) exhibiting pivotal activities controlling the
inflammatory and associated acute phase protein response. Unlike many other cytokines that exert
their influence at the local cellular level, IL-6 has systemic activity. Elevated serum
concentrations of IL-6 can be detected using bioassay, in harbor seal and killer whale serum,
from animals exhibiting various inflammatory conditions. Initial work focusing on the genetic
cloning of harbor seal (Phoca vitulina), killer whale (Orcinus orca) and sea otter
(Enhydra lutris nereis) cDNA sequences suggests that IL-6 is a well conserved molecule
between mammalian species. Expression of these cloned genes is currently underway for the
production of species-specific antibodies, reagents, and development of immunoassays.
C-reactive protein (C-RP) is an important liver-derived acute-phase protein
found in serum. Rapid increases in serum concentrations (ranging from 5-200 mg/L) can be
correlated with a variety of inflammatory conditions in many different mammalian species. Harbor
seal C-RP has been purified from acute phase serum by phosphoryl-choline and protein A affinity
chromatography. Sequencing of an internal amino acid peptide of this purified protein
demonstrates a high homology with human and murine CRP. Using a panel of specific
monoclonal antibodies against this protein work is currently underway to establish a sensitive
capture immuno-assay for serum C-RP for routine diagnostic use.