DNA-based immunisation against rabies and rabies-related viruses: towards multivalent vaccines.

Prototypes of multivalent DNA vaccines against lyssaviruses (LV: rabies and rabies-related viruses) and other viruses were developed using chimaeric LV glycoprotein (cLVG) DNA and cLVG DNA carrying foreign epitopes. cLVG is composed of the N-terminal half of an LV genotype (GT) containing antigenic site II, the C-terminal half of GT containing antigenic site III, as well as the transmembrane and cytoplasmic domains of the same or a different GT. Both antigenic sites induced virus neutralizing antibodies (VNAb). Foreign B and T cell epitopes inserted between the two halves of cLVG correspond to the B cell C3 neutralisation epitope of poliovirus VP1 protein and to the H2d CMH I restricted T cell epitope of the nucleoprotein of the lymphocytic choriomeningitis virus (LCMV). In mice and dogs homogenous rabies virus G DNA induced protection against wild-type rabies virus whereas cLVG protected against lyssaviruses. cLVG DNA carrying foreign epitopes induced VNAb against LV and poliovirus and protection against LCMV. The results obtained clearly demonstrate the potential usefulness of cLVG for the development of multivalent vaccines against viral diseases, including rabies and zoonoses.