Phagocytosis of alveolar macrophages of pyridoxine-deficient rats.

We measured phagocytosis of opsonized sheep red blood cells by alveolar macrophages (AM) of rats fed a diet with or without pyridoxine for 4 weeks. In pyridoxine-deficient (DEF) and pair-fed control (PF) groups AM showed a higher degree of phagocytosis than those of rats in the ad libitum-fed control (AL) group. After in vitro treatment with a macrophage-activating factor (MAF), such as lymphokines, for 4 hours at 37 degrees C, AM from the PF and AL groups showed a greater enhancement of phagocytic activity than AM from the DEF group, which was slightly enhanced. When the effect of MAF prepared from splenic cells of rats of the PF or DEF groups on the phagocytosis of AM was observed, MAF from the PF group showed an approximate 35% increase of phagocytic ability compared to the supernatant of splenic cells cultured with medium only. However, MAF from the DEF group had no effect on phagocytosis. These results suggest that pyridoxine deficiency affects not only phagocytic function of AM responsible for host defense in the lung but also MAF production by splenic cells.