Interleukin-2 (IL-2) incorporation in liposomes was studied under different conditions. Information was obtained on the mechanism of interaction of glycosylated recombinant IL-2 with liposomal bilayers. This information was utilized to formulate liposomes with high levels of incorporated IL-2. Multilamellar vesicles were prepared by hydration of a lipid film with an IL-2 solution. The incorporation efficiency, measured with a bioassay after forced release of IL-2 from the vesicles, was strongly dependent on the charge of the liposomes and the pH and ionic strength of the hydration medium. Negatively charged liposomes composed of phosphatidylcholine/ phosphatidylglycerol (9:1) and prepared with IL-2 dissolved in 10 mM NaAc/270 mM glycerol, 0.1% BSA, pH 5, showed the highest incorporation efficiency (81%) among the investigated preparations. This type of liposome was selected for further study. Electrostatics play a crucial role in the process of IL-2 association with this type of liposome. Initial studies concerning induction of protective tumor immunity by immunization with reconstituted membranes with mu-ramyl tripeptide phosphatidylethanolamine indicate that coinjection of IL-2-containing liposomes provided a significant enhancement of the immune response. Pharmaceutical Research Pharmaceutical Research Look Inside The American Association of Pharmaceutical Scientists The American Association of Pharmaceutical Scientists Other actions Export citation Register for Journal Updates About This Journal Reprints and Permissions Add to Papers Share Share this content on Facebook Share this content on Twitter Share this content on LinkedIn

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Pharmaceutical Research
Department of Medical Microbiology and Infectious Diseases

Bergers, E, den Otter, W, Dullens, H.F.J, Kerkvliet, S, & Crommelin, D.J.A. (1993). Interleukin-2-containing liposomes: Interaction of interleukin-2 with liposomal bilayers and preliminary studies on application in cancer vaccines. Pharmaceutical Research, 10(12), 1715–1721. doi:10.1023/A:1018913912580