ACTIVATION OF TUMORICIDAL PROPERTIES IN HUMAN-BLOOD MONOCYTES BY LIPOSOMES CONTAINING LIPOPHILIC MURAMYL TRIPEPTIDE

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  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (5) , 2010-2014
Abstract
Peripheral blood monocytes were isolated from normal human donors by separation on a continuous Percoll gradient and adherence to yield preparations of blood monocytes with a high degree of purity (> 99%). The monocytes were incubated in vitro with medium alone or multilamellar liposomes that contained either a lipophilic derivative of muramyl dipeptide, muramyl tripeptide (MTP-PE), or medium. The cytotoxic properties of the monocytes were assessed by an in vitro radioisotope release assay against various allogeneic targets. Monocytes that have phagocytosed liposomes containing MTP-PE were rendered tumoricidal. These monocytes lysed cells of 3 tumorigenic lines but not cells of two nontumorigenic lines. The ability of MTP-PE-activated human blood monocytes to recognize and selectively lyse neoplastic cells was also demonstrated under cocultivation conditions. Human blood monocytes can be rendered tumoricidal after interaction with liposomes containing MTP-PE.