Tri-O-tolyl phosphate neurotoxicity: lack of evidence for autoimmunologic involvement.

Studies on the involvement of autoimmunity in the pathogenesis of tri-O-tolyl phosphate (TOTP) induced neurotoxicity in chickens were conducted. Immunosuppressive therapy including gamma-radiation and drug treatments was utilized to determine its effects on the neurotoxic syndrome. Whole-body gamma-irradiation up to 1020 roentgens failed to show any consistent protection from the TOTP induced paralysis. Therapy involving prednisone alone or in combination with 6-mercaptopurine and antilymphocyte serum likewise indicated no protection. Stimulation of humoral and cellular immunity by TOTP was investigated. Complement fixation, precipitation tests, splenic migration inhibition, and skin tests did not indicate stimulation of autoimmunity toward nervous tissue or liver. The present investigation was unable to demonstrate primary involvement of an autoimmune nature in the neurotoxicity produced by TOTP in the chicken.