EFFECTS OF IN-VIVO GENERATION OF OXYGEN-FREE RADICALS ON IMMUNE RESPONSIVENESS IN RABBITS

Oxygen free radicals (OFRs) generated during biological processes are reportedly involved in the pathogenesis of several disease states and various reports have indicated that oxidative stress may alter immune competence. Hence, effects of in-vivo generation of OFRs by using xant hine/xanthine oxidase (X/XO) system on immune responsiveness were eval uated in rabbits. Intravenous injections of xanthine (0.14 mg/kg) alon g with xanthine oxidase (2 U/Kg) following primary and secondary immun izations of animals with sheep red blood cells (SRBC) significantly at tenuated the primary and secondary antibody responses respectively. In tests for cell-mediated immunity, tuberculin sensitivity and leucocyt e migration inhibition were also decreased significantly in sensitized animals following X/XO treatment. The observed changes in both humora l and cell-mediated immune responses following such in-vivo generation of OFRs indicate a possible nexus between OFR generation and immune s uppression. (C) 1997 Elsevier Science B.V.