ABSTRACT
The task of the immune system appears reasonably simple: to fend off invasion by foreign pathogens or prevent the growth of malignant tissues, using a network of interacting cells and chemical messengers. In practice, however, the immune system is highly complex and its function difficult to characterize, often rendering an assessment of its ‘status’ or ‘health’ extremely challenging. Although comparative studies have found that some specific differences exist between pinnipeds and other mammals, the immune system of pinnipeds shares many basic features with other species (Cavagnolo, 1979; Ross et al., 1994). Many of the functional assays used in assessing immune function in laboratory animals have been shown to be applicable to pinnipeds. Disease outbreaks among pinnipeds represent complex ecological events under natural circumstances (Hall et al., 1992a; Thompson and Hall, 1993), but the presence of high concentrations of immunotoxic chemicals in the tissues of these animals represents an additional variable requiring scrutiny.
