Antibacterial functions of macrophages in experimental protein calorie malnutrition. i. description of the model, morphologic observations, and macrophage surface IgG receptors

An experimental protein-calorie malnutrition was produced in weanling SpragueDawley rats. The model resembles human malnutrition with respect to weight loss, inanition, angular stomatitis, anemia, lymphopenia, hypoproteinemia with hypoalbuminemia, and marked thymic involution. In addition, systemic invasion by gramnegative rods was documented. However, no edema was produced, and animals did not survive for longer than six weeks on the protein-deficient diet. One percent glycogen was found to be a satisfactory nonprotein stimulus for induction of a peritoneal exudate consisting primarily of young macrophages. Electron microscopy showed that morphologic events of phagocytosis and degranulation proceeded normally in macrophages from protein-deficient animals. In addition, cell surface receptors for IgG were preserved under these experimental conditions. These data indicate that weanling rats may be employed as a small animal model for severe, fulminant protein-calorie malnutrition in humans.