Lyssavirus glycoproteins expressing immunologically potent foreign B cell and cytotoxic T lymphocyte epitopes as prototypes for multivalent vaccines

Truncated and chimeric lyssavirus glycoprotein (G) genes were used to carry and express nonlyssavirus B and T cell epitopes for DNA-based immunization of mice, with the aim of developing a multivalent vaccine prototype. Trunc ated G (GPVIII) was composed of the C-terminal half (aa 253-503) of the Pas teur rabies virus (PV: genotype 1) G containing antigenic site III and the transmembrane and cytoplasmic domains. The chimeric G (GEBL1-PV) was compos ed of the N-terminal half (aa 1-250) of the European bat lyssavirus 1 (geno type 5) G containing antigenic site II linked to GPVIII. Antigenic sites II and III are involved in the induction of virus-neutralizing anti bodies. T he B cell epitope was the C3 neutralization epitope of the poliovirus type 1 capsid VP1 protein. The T cell epitope was the H2(d) MHC I-restricted epi tope of the nucleoprotein of lymphocytic choriomeningitis virus (LCMV) invo lved in the induction of both cytotoxic T cell (CTL) production and protect ion against LCMV. Truncated G carrying foreign epitopes induced weak antibo dy production against rabies and polio viruses and provided weak protection against LCMV, In contrast, the chimeric plasmid containing various combina tions of B and CTL epitopes elicited simultaneous immunological responses a gainst both parental lyssaviruses and poliovirus and provided good protecti on against LCMV, The level of humoral and cellular immune responses depende d on the order of the foreign epitopes inserted. Our results demonstrate th at chimeric lyssavirus glycoproteins can be used not only to broaden the sp ectrum of protection against lyssaviruses, but also to express foreign B an d CTL epitopes, The potential usefulness of chimeric lyssavirus glycoprotei ns for the development of multivalent vaccines against animal diseases and zoonoses, including rabies, is discussed.