Abstract: The invention provides lipopeptide conjugates in which a cysteine that is double-substituted by a fatty acid is bonded by means of the carboxyl group to a highly soluble, physiologically compatible and non-immunogenic, polymeric conjugate group. The conjugates exhibit an excellent macrophage stimulant action and do not require addition solutizing. They can be used in a wide range of applications, in particular for stimulating macrophages, for stimulating antibody synthesis, for combating infection, as an immunostimulant, in particular in relation to tumors, for preventing and treating septicaemic shock, for would healing and as an adjuvant for vaccines.