Abstract

The immune system represents the interface between an individual's health and the ubiquitous pathogens it is exposed to. Nevertheless, it is highly sensitive to perturbations such as chemical pollutants and stress. Unfortunately, immune function testing has received little attention in clinical settings, especially in marine mammals. Stranded marine mammals represent a unique cross section of animals with different health problems, and the rehabilitation process involves close medical follow up, representing an ideal setting to validate the use of immune function testing as potential diagnostic and prognostic tool in marine mammal medicine. Testing for immune functions along with other health parameters was performed on stranded marine mammals under the care of the Mystic Aquarium and Institute for Exploration. For the first time in stranded pinnipeds, "normal" values, or more precisely, the odds of deviating from "normal" values when WBC were abnormal, were established. In both grey and harp seals, high WBC appeared to increase the odds of "abnormal" innate immune functions (phagocytosis and respiratory burst) as well as B cell proliferation. This is not surprising, as innate immune functions represent the first line of defense to insults such as bacterial infections, while a B cell-mediated antibody response is the hallmark of the acquired immune response to extra-cellular pathogens such as most bacteria. On the other hand, low WBC appeared to increase the odds of "abnormal" T lymphocyte proliferation. Reductions in WBC are often associated with viral infections, which are usually resolved by a T lymphocyte response to destroy infected cells. Overall, the findings of blind immunological testing are compatible with known general response patterns to different types of insults. Further analysis, to include the testing of more animals, will allow refinement of these results and determine the value of different immune parameters in health assessment.