Effect of stearoyl-N-acetylmuramyl-L-alanyl-D-isoglutamine on host resistance to Corynebacterium kutscheri infection in cortisone-treated mice.

Opportunistic corynebacteriosis was induced successfully by infection with Corynebacterium kutscheri in cortisone-treated mice and the ability of stearoyl-N-acetylmuramyl-L-alanyl-D-isoglutamine derivatives in phosphate buffered saline (PBS) solution or encapsulated into liposomes for restoring impaired resistance was examined. 6-O-Stearoyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (L18-MDP) in liposomes and N alpha-acetyl muramyl-L-alanyl-D-isoglutaminyl-N epsilon-stearoyl-L-lysine (MDP-Lys-L18) both in PBS solution and in liposomes were shown to restore depressed resistance to infection of C. kutscheri when injected intravenously before infection. Treatment with L18-MDP in cortisone-treated mice inhibited growth of C. kutscheri in the liver and kidney for as long as three days after infection.