T-2 toxin-enhanced resistance against listeriosis in mice: importance of gastrointestinal lesions.

The role of T-2 toxin-induced gastrointestinal lesions in T-2 toxin-enhanced resistance to listeriosis in mice was evaluated. The T-2 toxin-induced lesions did not cause a starvation effect sufficient to enhance resistance to listeriosis. Administration of polymyxin E markedly reduced the gram-negative intestinal microflora and did not eliminate the toxin-induced resistance to listeriosis. The T-2 toxin did not cause an increased expression of Ia surface antigens on peritoneal macrophages. Thus, toxin-induced anorexia and starvation or absorption of gram-negative intestinal bacteria and endotoxins through toxin-induced gastrointestinal lesions did not account for the enhancing effect of T-2 toxin on resistance to Listeria monocytogenes infection in mice.