The influence of source and quantity of protein upon the development of immunity and resistance to African trypanosomiasis

Abstract

Though it is well documented that severe protein deprivation inhibits the development of the immune response and exacerbates certain infections, little has been done to study the effects of native diets upon endemic diseases or immunity. Therefore, protein-restricted diets were formulated for mice to mimic the sources and amounts measured in human diets of the Batouri region of Cameroon, endemic for African trypanosomiasis. Weanling C57BL/6 female mice were fed a diet that contained 73% of the recommended daily allowance (RDA) of protein. The sources of protein were all plant (cornmeal), all animal (casein), or a ratio that reflected the native diet (2.2 parts cornmeal to 1 part casein). Diets were isocaloric on a weight basis, equal in lipids, and adequate in vitamins and minerals. Control mice were fed lab chow or 2 times the RDA of animal protein (casein). Mice fed plant or native diets survived infections with Trypanosoma brucei gambiense at higher rates than mice fed the other three diets. To determine if this resistance was immunologic in origin, mice were immunized with sheep erythrocytes (SE) or TNP-Ficoll. The plaque-forming cell response was directly related to survival. Therefore, cornmeal was an adequate source of protein for the development of immunity and resistance.