Enhanced immunostimulant activity and protective effect of a synthetic lipopeptide after liposomization against Plasmodium berghei infection in mice

The immunostimulant activity of non-pyrogenic, sugar-free immunomodulator l ipopeptide, Ala-D-Glu(Gly-Lys-CO.C11H23)-NH2 (comp. no 84/201), and its lip osomized formulation has been studied. Liposomization of this lipopeptide s ignificantly enhanced its antigen specific as well as nonspecific immune re sponses, as compared to the free lipopeptide. The liposomized formulation o f lipopeptide significantly stimulated both the antibody and delayed-type h ypersensitivity responses in Balb/c mice, and also enhanced nonspecifically the macrophage migration index, phagocytic activity and incorporation of C -14 glucosamine in peritoneal macrophages of the mice that received pretrea tment with this preparation. Further, the mice that received pretreatment w ith the liposomized preparation strongly resisted lethal P. berghei infecti on and consequently survived for longer period of time,,;. These results, i ndicate that liposomization of the compound no 84/201 significantly improve s its ability to enhance not only antigen-specific immune response but also the nonspecific host's resistance against infections.