MYCOTOXIN T-2 AND AFLATOXIN B-1 AS IMMUNOSUPPRESSORS IN MICE CHRONICALLY INFECTED WITH TOXOPLASMA-GONDII

The aim of this study was to determine whether repeated ingestion of m ycotoxin T-2 (T2) or aflatoxin B-1 (AFL) at low doses could contribute to the activation of toxoplasmosis in experimentally infected mice. M ice were divided into two groups: Control (C) and Infected (I). The cy st-forming Beverley strain of Toxoplasma gondii was used to produce th e infection one month before treatment with mycotoxins. Mycotoxins wer e given intragastrically for a 50-day period. The average weight gain was reduced in the groups treated with mycotoxins. Mice developed spec ific IgG to T. gondii. Histopathological studies showed severe encepha litis in all groups infected. The number of unruptured and ruptured cy sts was established and the severity of the lesions was evaluated, the groups treated with mycotoxins being the most severely affected. Immu nohistochemical studies of the brain showed free antigen in tissues su rrounding ruptured cysts. It is suggested that low and repeated doses of mycotoxins, necessary to produce a subclinical intoxication, precip itate Toxoplasma cyst rupture and consequently the activation of chron ic toxoplasmosis. (C) 1996 W.B. Saunders Company Limited