Homotypic and heterotypic protection against influenza virus infection in mice by recombinant vaccinia virus expressing the haemagglutinin or nucleoprotein gene of influenza virus

¹ Department of Virology and Rickettsiology, National Institute of Health, Shinagawa-ku, Tokyo 141,
The² Second Department of Surgery, Teikyo University School of Medicine, Itabashi-ku, Tokyo 173
³ Corporate Research and Development Laboratory, Tonen Corporation, Ohi-machi, Saitama 354,
⁴ Institute for Virus Research, Kyoto University, Sakyo-ku, Kyoto 606
and⁵ Department of Veterinary Radiology, Nihon University, Fujisawa, Kanagawa 252, Japan

Recombinant vaccinia virus expressing the influenza virus haemagglutinin (HA) or nucleoprotein (NP) genes from A/SW/Hong Kong/1/74 (H1N1) under the control of a hybrid promoter containing the P7.5 early promoter element and promoter of the gene encoding the major protein of cowpox virus A type inclusion body was constructed to investigate protective immunity against homologous and heterologous viruses in mice. These recombinant vaccinia viruses produced authentic influenza virus HA and NP in infected cells. The recombinant vaccinia virus-influenza virus HA conferred efficient subtype-specific protection although mice challenged with heterologous influenza viruses underwent initial infection. By contrast, immunization with the recombinant vaccinia-influenza virus NP limited virus multiplication in the lungs against challenge infection with all H1N1 and H3N2 influenza viruses examined, although less efficiently. These results will prompt the re-examination of the possibility of using the recombinant vaccinia virus-influenza virus NP as a cross-protective vaccine