Modulation of immune parameters of roach, Rutilus rutilus, exposed to untreated ECF and TCF bleached pulp effluents

The present study was designed to assess the effects of elemental chlorine free (ECF) and totally chlorine free (TCF) pulp and paper mill effluents on the immune defence of the roach (Rutilus rutilus). Fish were exposed for 5 weeks to concentrations of 0, 0.6, 2, 6 and 20% of untreated effluents from ECF or TCF bleaching processes. In order to study the capability to respond to foreign antigens the fish were immunised with bovine gamma-globulin (BGG) 3 weeks before sampling. The numbers of anti-BGG antibody-secreting cells and immunoglobulin-secreting cells in the spleen and blood, as well as the levels of the anti-BGG antibodies and concentrations of immunoglobulin in plasma and the proliferation of lymphocytes after mitogenic activation were determined. In addition, phagocytosis-related functions: respiratory burst activity and migration of leukocytes, were measured. Formation of specific anti-BGG antibody-secreting cells in the blood and immunoglobulin-secreting cells in the spleen and blood were suppressed in the fish exposed to a high concentration (20%) of ECF effluent. Similarly, the level of anti-BGG antibody and the stimulation indices of Concanavalin A-stimulated proliferation responses in vitro were lower in these fish. A decreased migration of granulocytes was observed in the fish exposed to 0.6-2% of ECF and TCF effluents. These results demonstrate that untreated ECF and TCF effluents significantly affected the immune parameters of the roach. Taken as a whole, fish exposed to TCF effluent showed less immunomodulation than those exposed to EFC effluent. (C) 2000 Elsevier Science B.V. All rights reserved.