A Viable Recombinant Rhabdovirus Lacking Its Glycoprotein Gene and Expressing Influenza Virus Hemagglutinin and Neuraminidase Is a Potent Influenza Vaccine

Abstract

The emergence of novel influenza viruses that cause devastating human disease is an ongoing threat and serves as an impetus for the continued development of novel approaches to influenza vaccines. Influenza vaccine development has traditionally focused on producing humoral and/or cell-mediated immunity, often against the viral surface glycoproteins hemagglutinin (HA) and neuraminidase (NA). Here, we describe a new vaccine candidate that utilizes a replication-defective vesicular stomatitis virus (VSV) vector backbone that lacks the native G surface glycoprotein gene (VSV⌬G). The expression of the H5 HA of an H5N1 highly pathogenic avian influenza virus (HPAIV), A/Vietnam/1203/04 (VN1203), and the NA of the mouse-adapted H1N1 influenza virus A/Puerto Rico/8/34 (PR8) in the VSV⌬G vector restored the ability of the recombinant virus to replicate in cell culture, without the requirement for the addition of trypsin. We show here that this recombinant virus vaccine candidate was nonpathogenic in mice when given by either the intramuscular or intranasal route of immunization and that the in vivo replication of VSV⌬G-H5N1 is profoundly attenuated. This recombinant virus also provided protection against lethal H5N1 infection after a single dose. This novel approach to vaccination against HPAIVs may be widely applicable to other emerging strains of influenza virus. IMPORTANCEPreparation for a potentially catastrophic influenza pandemic requires novel influenza vaccines that are safe, can be produced and administered quickly, and are effective, both soon after administration and for a long duration. We have created a new influenza vaccine that utilizes an attenuated vesicular stomatitis virus (VSV) vector, to deliver and express influenza virus proteins against which vaccinated animals develop potent antibody responses. The influenza virus hemagglutinin and neuraminidase proteins, expressed on the surface of VSV particles, allowed this vaccine to grow in cell culture and induced a potent antibody response in mice that was effective against infection with a lethal influenza virus. The mice showed no adverse reactions to the vaccine, and they were protected against an otherwise lethal influenza infection after only 14 days postvaccination and after as many as 140 days postvaccination. The ability to rapidly produce this safe and effective vaccine in cell culture is additionally advantageous.

Chikungunya, Influenza, Nipah, and Semliki Forest Chimeric Viruses with Vesicular Stomatitis Virus: Actions in the Brain

“…In contrast, the same intranasal inoculation with VSVΔG-CHIKV (n ϭ 8) and VLV (n ϭ 6) showed complete safety, with all mice surviving to the end of the experiment 42 days postinoculation. Although VSVΔG-H5N1 is nonpathogenic in adult mice outside the brain (45,46), here, we found it to be lethal after intranasal inoculation of P14 mice, with only a single survivor out of a large cohort (n ϭ 23) and almost all the mice succumbing to the virus within 4 to 10 days of inoculation (Fig. 4).…”

“…All the chimeric viruses discussed here have shown efficacy in acting in a vaccine capacity to protect against the respective virus antigens, including Nipah virus, chikungunya virus, and influenza virus (44,(46)(47)(48)(49). By virtue of their safety in both adult and developing brains, VSVΔG-CHIKV and VLV showed the least adverse neurotropism among the chimeric viruses tested; these viruses merit further investigation for potential applications, including vaccination.…”

“…The VSV glycoprotein gene was deleted (VSVΔG) in four of the viruses, VSVΔG-CHIKV, VSVΔG-H5N1, VSVΔG-Nipah F, and VSVΔG-Nipah G. VLV was generated from the Semliki Forest virus RNA replicon encoding VSV G and the four nonstructural proteins of SFV but none of the SFV structural proteins (37,39). All four recombinants have been tested as possible vaccine vectors (38,(44)(45)(46)(47)(48)(49). Three additional recombinant VSVs were used for control purposes; all three have been previously used to test intracranial safety (18,41,50).…”

“…The chimera incorporated functional CHIKV glycoproteins into the viral envelope in place of VSV G (44). VSVΔG-H5N1 has the VSV G gene deleted, and in its place were substituted the two influenza virus genes, H5 and N1, as described in detail previously (45,46). Genomic diagrams of the recombinant chimeric viruses are shown in Fig.…”

Vaccination with Vesicular Stomatitis Virus-Vectored Chimeric Hemagglutinins Protects Mice against Divergent Influenza Virus Challenge Strains

“…In order to create a vaccination strategy that exploits the advantages of live viral vectors, while at the same time limiting exposure to a single viral vector system, vesicular stomatitis virus (VSV) vectors with different vesiculovirus envelope proteins (17) have been generated that can be used in primeboost vaccination. We have previously shown that VSV vectors can express influenza HA molecules and that these VSV-HA constructs protect against challenge with homologous influenza viruses (18)(19)(20). Here, we show that VSV-cHA vaccines administered by different routes (intramuscular [i.m.]…”