Influence of dietary protein on DDT-induced immune responsiveness in rats.

The influence of protein deficiency was evaluated on immune responsiveness after subchronic DDT exposure in albino rats. Rats were given 20%, 12% and 3% protein diets and exposed to DDT (20, 50 or 100 ppm) for 4 weeks. DDT (50 and 100 ppm) induced humoral and cellular immune suppression only in rats fed on 3% protein diet. There was (a) an increase in the albumin/globulin ratio, (b) suppression in IgM and IgG levels, and (c) attenuation in the tetanus toxoid-induced antibody responses. Further, in rats immunized with tetanus toxoid, the leucocyte and macrophage migration inhibition were also attenuated. Moreover, these animals maintained on 3% protein diet showed depression in humoral and cellular immune responses to antigen in a dose-dependent pattern after exposure to DDT at dose levels which were not immunosuppressive for rats on 12% or 20% protein diet. These results suggest that dietary protein content may predispose to the immunotoxic effects of DDT exposure, and also be a crucial determinant in DDT detoxification.