Vaccine molecules

A DNA vaccine comprising first and second nucleic acid constructs encoding first and second fusion proteins comprising a targeting unit, a heterodimerization unit, and an antigenic unit in operable association, wherein said antigenic unit for each of said first and second fusion proteins are variant target antigenic proteins and wherein when said first and second nucleic acid constructs are introduced into a cell the first and second fusion proteins are expressed and associate to form a first heterodimeric protein via association of said heterodimerization units, wherein said heterodimerization unit in one of said first and second nucleic acid constructs is an ACID heterodimerization unit and the heterodimerization unit in the other of the first and second nucleic acid constructs is a BASE heterodimerization unit that interact to form an ACID/BASE heterodimerization domain is said first heterodimeric protein.