INNATE IMMUNE FUNCTION AS A BIOINDICATOR OF POLLUTION STRESS IN FISH

Immunotoxicological studies, based on processing of samples in the fie ld and laboratory, were conducted on fish collected from a stream rece iving point-source contaminants near its headwaters. Previous studies in this stream have revealed that cytochrome P4501A activity, liver so matic indices, macrophage aggregates, and parasitic liver lesions are significantly elevated in sunfish with the degree of impact decreasing with distance from the contaminant source, Fish collected from each s ampling site were equally divided, One group was sacrificed in the fie ld and the spleen and anterior kidney tissues were removed and placed in buffer on ice. The other group was kept in MS-222 for 2 hr and tran sported to the laboratory for processing. The spleen and anterior kidn ey from each fish were then prepared as a single cell suspension and s hipped overnight to Mississippi State University. Cells were then eval uated for PMA-stimulated phagocyte oxidative burst and nonspecific cyt otoxic cell (NCC) activity against K562 tumor targets. Oxidative burst responses were dramatically suppressed in both groups at sampling sit es near the headwaters but returned to reference levels further downst ream. There were no differences between processing strategies at each station. NCC activities did not follow gradient-response patterns obse rved with phagocyte oxidative burst data and there were inconsistent d ifferences between processing strategies at each site. These data indi cate that simple immune function assays, such as phagocyte oxidative b urst responses, can be used as a ancillary bioindicator in fish health monitoring and that immune function in these fish can be reliably ass essed even if samples are not immediately processed. (C) 1996 Academic Press, Inc.