Melanoma vaccine based on the vector of membrane fusogenic liposomes

Membrane fusogenic liposomes can deliver encapsulated contents into the cytoplasm directly in a Sendai virus fusion-dependent manner. Based on the high delivery rates into the cytoplasm, membrane fusogenic liposomes were investigated as an antigen delivery vehicle. The membrane fusogenic liposomes were formulated by fusing simple liposomes with ultraviolet inactivated Sendai virus. The vaccine was prepared by encapsulating mixture antigen into the simple liposomes, and then fusing with Sendai virus. The antigen, mixture proteins were extracted from B16 melanoma cells. Membrane fusogenic liposomes were characterized for their sizes and shape by laser light granule analysis instrument and transmission electron microscope (TEM). The cytotoxic T lymphocyte (CTL) responses level was evaluated by the 51Cr release method. The positive expression of CD4+ and CD8+ cells, entrapment capacity of membrane fusogenic liposomes and the concentration of IgG in serum of immunized mice were measured. The vaccine, formulated with simple liposomes can induced systemic responses, but not CTL responses. However, membrane fusogenic liposomes-formulated melanoma vaccine can elicit not only systemic immune responses but also strong CTL responses, and inhibit the accretion of tumor. Membrane fusogenic liposomesas a vector for use in anti-tumor vaccine therapy are feasible.