Effect of methyl esterification of isoglutamine residue in 6-O-acylated muramyl dipeptides on expression of immunopharmacological activities.

The effect of methyl esterification of the isoglutamine residue in 6-O-acylated muramyl dipeptide (MDP) on some biological activities was investigated. Methyl esterification influenced more or less the expression of all activities tested. The adjuvant and colony stimulating factor (CSF)-inducing activities of 6-O-acylated MDP analogs carrying a 3-hexadecanoyloxytetradecanoyl [C14-O-(C16)] group were stronger than those of the corresponding analogs carrying a 2-tetradecylhexadecanoyl (B30) group. Macrophage activation, i.e. induction of tumor necrosis factor (TNF) and promotion of phagocytosis, by 6-O-C14-O-(C16)-MDP methyl esters was weaker.