Mitogenic effect of bacterial peptidoglycans possessing adjuvant activity.

Two purified peptides extracted from E. coli or B. megaterium strongly stimulated the spleen lymphocytes of rabbits and of normal or nude mice. Both preparations can substitute for Mycobacteria in Freund's complete adjuvant. The peptidoglycan extracted from M. lysodeikticus by a similar procedure which lacks adjuvant activity, did not induce blast transformation. However, the monomere of the E. coli peptidoglycan was devoid of mitogenicity although it has also a marked adjuvant activity.