The present invention relates to the microbial immunogens engineered to bear α-gal epitope(s) for induction of potent humoral and cellular immune responses when administered to subjects having anti-Gal antibodies. In one embodiment, the present invention provides compositions and methods for propagating influenza virus in human, ape, Old World monkey or bird cells that have been engineered to express an α1,3galactosyltransferase (α 1,3GT) gene to produce virions bearing hemagglutinin molecules containing α-gal epitopes, to increase the immunogenicity of the influenza virus. In another embodiment, the present invention provides fusion proteins between influenza virus hemagglutinin and a microbial peptide or protein of interest, and enzymatic processing of this fusion protein to carry α-gal epitopes, to increase the immunogenicity of the microbial peptide or protein of interest.
