The present invention relates to a vaccine for increasing the immunogenicity of a tumor antigen thus allowing treatment of cancer, as well as a vaccine that increases the immunogenicity of a viral antigen, thus allowing treatment of viral infection, including immunodeficiency virus (HIV) infection. In particular, the present invention provides a fusion protein comprising a defensin fused to either a tumor antigen or viral antigen which is administered as either a protein or nucleic acid vaccine to elicit an immune response effective in treating cancer or effective in treating or preventing viral infection.
