An alternative way to broaden vaccine immunogenicity and increase its efficacy has been to use combination of plasmids encoding various antigens. For examples, cysteine proteinase (CP) a and b DNA vaccines are not protective when used individually, but immunization with a combination of both plasmids induces long-term protective immunity [34] . Alternatively, gene fusion has also been successively used to achieve expression of an antigenic fusion protein from a single plasmid construct [33] . Overall, expression of several antigens mostly resulted in increased efficacy, but this also depended on the antigen combination [13, 22, 23, 41, 45] .