Cellular communication between cells mediating the immune response occurs by the release of a group of soluble proteins known as cytokines. Produced by monocytes/macrophages and fibroblasts, interleukin 6 (IL-6) is a multi-functional cytokine with anti-inflammatory actions such as initiation of acute phase protein synthesis, stimulation of antibody production from B-lymphocytes and proliferation of haematopoetic cells. Unlike most cytokines that are produced and act on target cells locally, IL-6 has systemic activity and elevated serum concentrations can be reliably detected in individuals with inflammation, tumor growth, infection, tissue damage. Determination of serum IL-6 will provide a valuable assessment of marine mammal health.

In humans, IL-6 can be rapidly quantified by immunoassay. Unfortunately, these assays are species specific (i.e., systems used to determine IL-6 in humans do not work effectively in marine mammals). Currently, IL-6 can be measured in seal serum using cell specific bioassays. These methods are relatively time consuming. We are further characterizing IL-6 from several Pacific marine mammal species. To date, we have used degenerate bovine primers to amplify a fragment of the IL-6 gene of the harbor seal and killer whale. Using established molecular biology techniques, we hope to develop specific reagents for use in quantitative PCR or immunoassays that will in the future provide a rapid assay to accurately quantify serum IL-6.