Phagocytosis of Splenetic Neutrophils of Mice Enhanced by Orally Administered Peptidoglycan from Bifidobacterium thermophilum

A preparation of peptidoglycan (PG) of swine Bifidobacterium thermophilum was orally administered to SPF-BALB/C and ICR mice and its effect on phagocytosis splenetic neutrophils from PG administered mice was measured by chemiluminescent response (CL) and fluorometric analysis and the result was compared with that of non-treated mice. PG stimulated phagocytosis of neutrophils in a dose-dependent manner, whereas dosage exceeding the optimum concentration (500 μg) inhibited phagocytosis. The maximum effect on phagocytosis of neutrophils was observed at 3 days after administration of PG 500 μg. The result of fluorometric analysis was almost similar to that of CL. These results indicate that orally administered PG enhances the activity of the phagocytosis of splenetic neutrophils from mice.