Impairment of phagocytic process in macrophages from young and old mice by protein malnutrition.

In young (15 +/- 2 weeks old) and old (75 +/- 5 weeks old) Swiss mice fed a 4% protein diet ad libitum for 15 days, we studied the different steps of phagocytic processes of peritoneal macrophages. In young mice, adherence to tissue substrates was significantly increased, but spontaneous mobility, chemotaxis, attachment and ingestion of opsonized Candida albicans, and production of superoxide anion indicative of microbicidal capacity measured by the nitroblue tetrazolium (NBT) reduction were significantly decreased with respect to the corresponding young controls (mice fed with a standard 17% protein diet). Attachment and ingestion of C. albicans, and NBT reduction were also decreased in old protein-malnourished mice.