Cytokine-containing liposomes as vaccine adjuvants.

The ability of cytokines to regulate and augment an immune response makes them likely agents to be included in vaccines. The systemic use of cytokines as vaccine adjuvants has been hampered by toxicity at effective doses. More precise delivery of cytokines and immunogen can be achieved through the use of microparticle carriers such as liposomes. Several cytokines, including IL-2, IL-7, IL-6 and IFN-gamma have been shown to increase the adjuvant activity of liposomes. It may be possible to use certain cytokines to induce immunoglobulin production, others to induce cytotoxic T lymphocytes (CTL) and still others to promote IgA production at mucosal surfaces. An alternative to liposomes containing cytokines may be liposomes containing cytokine-inducing adjuvants such as MTPPE, MPL and QS21. This approach may produce undesirable immunomodulators as well as beneficial cytokines.