Impaired function of immune reactivity to Listeria monocytogenes in diet-fed mice.

Mice fed a diet high in cholesterol, lard, and sucrose were shown to exhibit an impairment of specific immunity to Listeria monocytogenes. Whereas titers of L. monocytogenes in livers of normal mice decreased rapidly after 6 days of infection, L. monocytogenes persisted in livers of diet-fed mice. Adoptive transfer experiments indicated that L. monocytogenes-immune spleen cells are generated in diet-fed mice. However, the function of immune spleen cells from donors of either nutritional status was impaired in diet-fed recipients. The results indicate that the site(s) of impairment of specific immunity to L. monocytogenes in diet-fed mice occurs at a stage beyond the generation of immune T-cells.