Abstract: The 3-O-[N-acetylmuramyl-D-isoglutaminyl]-1,2-di-O-palmitoyl-sn-glycerol derivative of formula I ##STR1## wherein the carbon atom marked with an asterisk * has the R or, respectively, the S configuration, possesses interesting pharmacological, in particular immunomodulating properties. It is particularly useful as an immunomodulant, as an adjuvant in vaccines and as a suppressing agent for IgE formation in e.g. type I allergies and atopical dermatitises.It is obtained by deprotection of a corresponding compound having one or more hydroxy group(s) in protected form.