Antibacterial functions of macrophages in experimental protein-calorie malnutrition. II. Cellular and humoral factors for chemotaxis, phagocytosis, and intracellular bactericidal activity.

Cellular and humoral aspects of the antibacterial activity of macrophages during experimental protein-calorie malnutrition were studied. There were no defects in chemotaxis or bactericidal activity of cells from protein-deficient animals, although phagocytosis-associated oxygen consumption and hexose monophosphate shunt activity were depressed. However, marked impairment of humoral chemotactic factors generated in the peritoneal cavity by glycogen injection and of heatlabile serum opsonins for Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Salmonella enteritidis was found. The studies suggested that some macrophage antibacterial functions measured in vitro are not altered in experimental acute protein-calorie malnutrition, but that serum factors, presumably complement-derived, would limit their in vivo function. Thymic involution and lymphocyte depletion would further impair in vivo cellular immune reactions affected by macrophages. This model may therefore prove useful for the study of specific aspects of cellular immunity in malnourished hosts and of specific rehabilitation strategies.