Abstract: Nucleic acids are disclosed encoding fusion proteins comprising the amino acid sequence of at least four non-attenuated HIV proteins selected from the group consisting of Vif, Vpr, Vpu, Vpx, Rev, Tat, and Nef, wherein the fusion protein does not contain a specific cleavage sequence for a cellular protease. Also disclosed are vectors comprising the nucleic acids and methods of preparing the fusion protein by transfecting a host cell with the nucleic acids or with the vectors containing the nucleic acids, expressing the fusion proteins, and recovering the fusion proteins.