Marine mammals are ideal sentinel species for human health due to exposure to the same oceans and consumption of the same foods. There have been many studies which demonstrate that wild Atlantic Bottlenose Dolphins are exposed to high levels of contaminants which lead to a suppressed immune system and are therefore more susceptible to opportunistic infections, many of which are zoonotic diseases. However, nearly no research has been done on determining defects in the immune cell population of dolphins, especially DCs which are essential for initiating an immune response. We hypothesize phenotypic and functional differences in the PBMC, including DC precursors, of wild dolphins as compared to managed dolphins. Specifically in this study, we have used terrestrial-specific antibodies and growth factors to characterize immune cells in PBMC and to generate monocyte-derived DCs. We have identified cross-reactive terrestrial antibodies that could detect immune cell subsets within PBMC, including B cells, T cells, NK cells, monocytes and APCs. Interestingly, using these antibodies we found significant changes in immune cell subsets within PBMC of wild and managed dolphins. Finally among the terrestrial DC growth factors tested we found rat GM-CSF and IL-4 generated DCs expressing higher levels of CD11c, CD14, CD40, CD80, CD86, MHC I and MHC II. Our findings allow us to further study defects in the immune cells, especially DCs, in response to environmental contaminants.