Cytotoxic responses induced by peptidoglycans with or without in vivo antitumor activity.

Cytotoxic responses mediated by effector cells stimulated in vivo were studied after ip injection in mice of peptidoglycans extracted from gram-positive bacteria. A comparison was done between Staphylococcus aureus peptidoglycan (PGS), which possessed an antitumor effect, and Micrococcus lysodeikticus peptidoglycan, which was ineffective against tumors. Both peptidoglycans induced similar effects on the modulation of T-cell cytotoxic response. Both were able to stimulate splenic and peritoneal nonspecific cytotoxicity against YAC-1 lymphoid tumor cells, but only PGS could induce cytotoxicity and cytostasis against solid tumor target cells.