Suppression of Sendai virus growth by treatment with N alpha-acetylmuramyl-L-alanyl-D-isoglutaminyl-N epsilon-stearoyl-L-lysine in mice.

Mice that received N alpha-acetylmuramyl-L-alanyl-D-isoglutaminyl-N epsilon-stearoyl-L-lysine [MDP-Lys (L18)] were resistant to Sendai virus infection. In these protected mice, a significant growth inhibition of the virus was confirmed repeatedly at 10(0.2) to 10(0.4) of haemadsorbing units at an early non-specific phase but not at a late virus-eliminating phase of the infection. Virus growth was enhanced by treatment with silica but not by treatment with anti-asialo GM1 serum in MDP-Lys (L18)-treated mice. Peritoneal adherent cells activated by MDP-Lys(L18) showed an enhanced uptake and ability to inactivate Sendai virus in vitro. Excess interferon production in MDP-Lys (L18)-treated mice was seen on day 1 but not on days 2 to 7 of the infection. The possible role of macrophages and interferon in providing non-specific protection against Sendai virus in the MDP-Lys (L18)-treated mice is discussed.