EFFECTS OF POLYCYCLIC AROMATIC-HYDROCARBONS ON THE LYMPHOCYTE MITOGENIC RESPONSES IN SPOT, LEIOSTOMUS-XANTHURUS

Several polycyclic aromatic hydrocarbons (PAH) modulate leukocyte activity in vertebrates.1 PAH require metabolic activation to ultimate carcinogenic forms,2 but it is unknown whether PAH metabolism is required to exert immunocyte modulation in fish. The Southern Branch of Elizabeth River, Virginia, is heavily contaminated with PAH, and fish collected from this system show high incidence of diseases and neoplasms.3,4 Because T lymphocytes play an important role in host-defense mechanisms in vertebrates, we designed several experiments to examine the effects of PA H on T cell activity in vivo and in vitro. Our results show that PAH suppress the proliferative responses of the lymphocytes and that this modulation may involve cytochrome P450-mediated PAH metabolism.