Zeng, Menghua

Background: 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 Dendritic Cells DCs that are essential for initiating an immune response. Hypothesis: We hypothesize phenotypic and functional differences in the Peripheral Blood Mononuclear Cells PBMC, including DC precursors, of wild dolphins as compared to managed dolphins. Methods: 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. Results: 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. Conclusion: Our findings allow us to further study defects in the immune cells, especially DCs, in response to environmental contaminants.

Background: Vaccines aid in saving lives from infections and biological warfare attacks. They should be effective in all target populations otherwise the likelihood that an unprotected person will transmit disease to a vulnerable individual is greatly increased. There is compelling evidence that smokers are less responsive to vaccination. We have reported that both therapeutic and prophylactic vaccines fail to protect and cure animals from disease due to negative effects of nicotine in biological activities of DCs. Using in vitro mouse culture system we have identified an appropriate TLR agonist capable of correcting the defects in DCs exposed to nicotine. Hypothesis: In order to translate these studies to human, we tested the hypothesis that appropriate TLR agonists will also correct the degrading effects of nicotine on human DCs and consequently DC-NK cross talk and T cell polarization. Methods: Monocyte-derived DCs were generated in culture media containing growth factors GM-CSF and IL-4 with or without nicotine treatment. DCs were activated with indicated TLR agonists and their phenotypes and cytokine profiles were analyzed by flow cytometry and ELISA, respectively. Results: Among the TLR agonists tested, we found that nicotine has less effect on human DC maturation in response to TLR4 plus TLR7/8 agonists as evidenced by expression levels of their costimulatory CD80/83/86/40 and antigen-presenting HLA-DR molecules as well as inflammatory cytokines IL-12, IL-10,TNF-α and IL-1β production. Conclusion: We are currently investigating whether these TLR agonists also augment human DC-NK bidirectional signals essential for T cell differentiation in a nicotinic environment.