Naked RNA immunization with replicons derived from poliovirus and Semliki Forest virus genomes for the generation of a cytotoxic T cell response against the influenza A virus nucleoprotein

• Published in: Journal of general virology Vol. 82; no. 7; pp. 1737 - 1747
• Main Authors: Vignuzzi, Marco, Gerbaud, Sylvie, van der Werf, Sylvie, Escriou, Nicolas
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01.07.2001
• Subjects: Animals; H-2 Antigens - immunology; Histocompatibility Antigen H-2D; Immunity, Cellular; Immunization; Immunodominant Epitopes - immunology; Influenza A virus; Influenza A virus - immunology; Influenza A virus - isolation & purification; Lung - virology; Major Histocompatibility Complex - immunology; Male; Mice; Mice, Inbred C57BL; NP antigen; NP protein; Nucleoproteins - genetics; Nucleoproteins - immunology; Orthomyxoviridae Infections - immunology; Orthomyxoviridae Infections - prevention & control; Orthomyxoviridae Infections - virology; Poliovirus; Poliovirus - genetics; Recombination, Genetic - immunology; Replicon - immunology; RNA, Viral - administration & dosage; RNA, Viral - immunology; Semliki Forest virus; Semliki forest virus - genetics; T-Lymphocyte Subsets - immunology; T-Lymphocytes, Cytotoxic - immunology; Vaccines, Synthetic - administration & dosage; Viral Load; Viral Vaccines - administration & dosage
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-82-7-1737

Unité de Génétique Moléculaire des Virus Respiratoires, URA 1966 CNRS, Institut Pasteur, 25 rue du Dr Roux, F-75724 Paris cedex 15, France 1 Author for correspondence: Nicolas Escriou. Fax +33 1 40 61 32 41. e-mail escriou{at}pasteur.fr The potential of RNA-based vaccines was evaluated for the generation of a protective immune response in the mouse model of influenza type A virus infection using the internal nucleoprotein (NP) as antigen. This antigen is of particular interest, since it has the potential to elicit protective cytotoxic T lymphocytes (CTL) against heterologous strains of influenza A virus. In view of the short half-life of RNA, self-replicating RNAs or replicons of the positive-stranded genomes of Semliki Forest virus (SFV) and poliovirus were engineered to synthesize the influenza A virus NP in place of their structural proteins. NP expression was demonstrated by immunoprecipitation after transfection of cells with RNA from the SFV (rSFV-NP) and poliovirus (r P1-E-NP) genome-derived replicons transcribed in vitro . C57BL/6 mice were injected intramuscularly with these synthetic RNAs in naked form. Both replicons, rSFV-NP and r P1-E-NP, induced antibodies against the influenza virus NP, but only mice immunized with the rSFV-NP replicon developed a CTL response against the immunodominant H-2D b epitope NP366. Finally, the protective potential of the CTL response induced by immunization of mice with rSFV-NP RNA was demonstrated by the reduction of virus load in the lungs after challenge infection with mouse-adapted influenza A/PR/8/34 virus and was comparable to the protective potential of the response induced by plasmid DNA immunization. These results demonstrate that naked RNA immunization with self-replicating molecules can effectively induce both humoral and cellular immune responses and constitutes an alternative strategy to DNA immunization.