Vaccination with Recombinant RNA Replicon Particles Protects Chickens from H5N1 Highly Pathogenic Avian Influenza Virus

Antivector immunity limits the response to homologous boosting for viral vector vaccines. Here, we describe a new, potent vaccine vector based on replication-competent vesicular stomatitis virus pseudotyped with the glycoprotein of the lymphocytic choriomeningitis virus (VSV-GP), which we previously showed to be safe in mice. In mice, VSV and VSV-GP encoding ovalbumin (OVA) as a model antigen (VSV-OVA and VSV-GP-OVA) induced equal levels of OVA-specific humoral and cellular immune responses upon a single immunization. However, boosting with the same vector was possible only for VSV-GP-OVA as neutralizing antibodies to VSV limited the immunogenicity of the VSV-OVA boost. OVA-specific cytotoxic T-lymphocyte (CTL) responses induced by VSV-GP-OVA were at least as potent as those induced by an adenoviral state-of-the-art vaccine vector and completely protected mice in a Listeria monocytogenes challenge model. VSV-GP is so far the only replication-competent vaccine vector that does not lose efficacy upon repeated application. IMPORTANCE Although there has been great progress in treatment and prevention of infectious diseases in the past

Section: Discussionmentioning

confidence: 99%

VSV-GP: a Potent Viral Vaccine Vector That Boosts the Immune Response upon Repeated Applications

Tober

Bánki

Egerer

et al. 2014

“…Recombinant modified vaccinia virus Ankara expressing the RNA polymerase of the T7 phage (MVA-T7) was a kind gift from Gerd Sutter (LMU, Munich, Germany) (45). Recombinant VSV*⌬G(HA H5 ) and VSV*⌬G(HA H1 ) expressing the HA antigen of A/Yamaguchi/7/04 (H5N1) and A/duck/Italy/1447/05 (H1N1), respectively, have been reported previously (46). The HPAIV A/chicken/Yamaguchi/7/04 (H5N1) (47) A/swine/USA/1976/31 (H1N1) was purchased from the American Type Culture Collection (Manassas, VA, USA).…”

Section: Methodsmentioning

confidence: 99%

“…The cDNAs encoding segments 4 and 6 of A/swine/Belzig/2/01 (H1N1), segment 4 of A/turkey/Italy/3675/99 (H7N1), and segment 6 of A/swan/Potsdam/62/81 (H7N7) were generated by reverse transcription of total RNA isolated from either virusinfected MDCK cells or the allantoic fluid of infected chicken embryos (46). The cDNAs encoding all eight RNA segments of A/chicken/Yamaguchi/7/04 (H5N1) and A/WSN/33 (H1N1) were kindly provided by Yoshihiro Sakoda (Hokkaido University, Sapporo, Japan) and Gabriele Neumann (University of Wisconsin-Madison, Madison, WI, USA), respectively.…”

Section: Methodsmentioning

confidence: 99%

Biological and Protective Properties of Immune Sera Directed to the Influenza Virus Neuraminidase

Halbherr¹,

Ludersdorfer²,

Ricklin³

et al. 2015

Self Cite

The envelope of influenza A viruses contains two large antigens, hemagglutinin (HA) and neuraminidase (NA). Conventional influenza virus vaccines induce neutralizing antibodies that are predominantly directed to the HA globular head, a domain that is subject to extensive antigenic drift. Antibodies directed to NA are induced at much lower levels, probably as a consequence of the immunodominance of the HA antigen. Although antibodies to NA may affect virus release by inhibiting the sialidase function of the glycoprotein, the antigen has been largely neglected in past vaccine design. In this study, we characterized the protective properties of monospecific immune sera that were generated by vaccination with recombinant RNA replicon particles encoding NA. These immune sera inhibited hemagglutination in an NA subtype-specific and HA subtype-independent manner and interfered with infection of MDCK cells. In addition, they inhibited the sialidase activities of various influenza viruses of the same and even different NA subtypes. With this, the anti-NA immune sera inhibited the spread of H5N1 highly pathogenic avian influenza virus and HA/NA-pseudotyped viruses in MDCK cells in a concentration-dependent manner. When chickens were immunized with NA recombinant replicon particles and subsequently infected with low-pathogenic avian influenza virus, inflammatory serum markers were significantly reduced and virus shedding was limited or eliminated. These findings suggest that NA antibodies can inhibit virus dissemination by interfering with both virus attachment and egress. Our results underline the potential of high-quality NA antibodies for controlling influenza virus replication and place emphasis on NA as a vaccine antigen. IMPORTANCEThe neuraminidase of influenza A viruses is a sialidase that acts as a receptor-destroying enzyme facilitating the release of progeny virus from infected cells. Here, we demonstrate that monospecific anti-NA immune sera inhibited not only sialidase activity, but also influenza virus hemagglutination and infection of MDCK cells, suggesting that NA antibodies can interfere with virus attachment. Inhibition of both processes, virus release and virus binding, may explain why NA antibodies efficiently blocked virus dissemination in vitro and in vivo. Anti-NA immune sera showed broader reactivity than anti-HA sera in hemagglutination inhibition tests and demonstrated cross-subtype activity in sialidase inhibition tests. These remarkable features of NA antibodies highlight the importance of the NA antigen for the development of next-generation influenza virus vaccines.

“…Recently, enhanced delivery technologies, such as electroporation (37,38), and improved immunogenicity by triggering innate immune cells have increased the efficacy of DNA vaccines in clinical trials (39). Vaccines based on mRNA or RNA replicons are immunogenic in a variety of animal models, including nonhuman primates (40)(41)(42)(43)(44). RNA replicons are derived from the genomes of RNA viruses, such as alphaviruses, and have been engineered by eliminating the genes encoding the structural proteins and replacing them with genes of interest.…”

mentioning

confidence: 99%

Induction of Broad-Based Immunity and Protective Efficacy by Self-amplifying mRNA Vaccines Encoding Influenza Virus Hemagglutinin

Brazzoli

Magini

Bonci

et al. 2016

137

130

Seasonal influenza is a vaccine-preventable disease that remains a major health problem worldwide, especially in immunocompromised populations. The impact of influenza disease is even greater when strains drift, and influenza pandemics can result when animal-derived influenza virus strains combine with seasonal strains. In this study, we used the SAM technology and characterized the immunogenicity and efficacy of a self-amplifying mRNA expressing influenza virus hemagglutinin ( IMPORTANCEIn this study, we describe protective immune responses in mice and ferrets after vaccination with a novel HA-based influenza vaccine. This novel type of vaccine elicits both humoral and cellular immune responses. Although vaccine-specific antibodies are the key players in mediating protection from homologous influenza virus infections, vaccine-specific T cells contribute to the control of heterologous infections. The rapid production capacity and the synthetic origin of the vaccine antigen make the SAM platform particularly exploitable in case of influenza pandemic.