An ultrastructural study of peritoneal mononuclear phagocytes from Corynebacterium parvum-injected mice.

Peritoneal mononuclear phagocytes harvested from mice 24 h after i.p. injection of C. parvum displayed hypertrophy of the Golgi and smooth endoplasmic reticulum complex with attendant increase in lysosome production. The ingested bacilli were identified within phagolysosomes, within which large myelin figures accumulated. In addition to heterophagic vacuoles, autophagosomes and lipid droplets were observed. These latter two inclusions may reflect a direct or indirect cytopathic effect of C. parvum on the phagocytes.