Adjuvant activity of mycobacterial fractions: adjuvant activity of synthetic N acetylmuramyl dipeptide and the related compounds

Abstract

Immunological activity of synthetic cell wall peptidoglycan subunits was examined in guinea pigs and mice. It was concluded that the minimal adjuvant active subunit of cell wall peptidoglycan for the induction of delayed type hypersensitivity to monoazobenzenearsonate N acetyl L tyrosine and for circulating antibody formation to bacterial α amylase and the thymus independent antigen DNP Ficoll was N acetylmuramyldipeptide, MurNAc L Ala D isoGln. N acetylmuramyldipeptide and 6 O stearoyl N acetylmuramyldipeptide showed no adjuvant activity in the generation of cell mediated cytotoxic effector cells in the spleens of C57Bl/6J mice after in vivo immunization with the allogeneic antigen mastocytoma P815 X2 cells, but N acetylmuramyldipeptide showed adjuvant activity after in vitro sensitization of C57Bl/6J mouse spleen cells to the alloantigen mitomycin C treated DBA/2 mouse spleen cells. It was also shown that 6 O stearoylation of N acetylmuramylpeptide could not potentiate the adjuvant activity of N acetylmuramyldipeptide. Mitogenic and antitumor activities were not observed in either N acetylmuramyldipeptide or 6 O stearoyl N acetylmuramyldipeptide in mouse systems.