Multiple-Clade H5N1 Influenza Split Vaccine Elicits Broad Cross Protection against Lethal Influenza Virus Challenge in Mice by Intranasal Vaccination

Abstract

BackgroundThe increase in recent outbreaks and unpredictable changes of highly pathogenic avian influenza (HPAI) H5N1 in birds and humans highlights the urgent need to develop a cross-protective H5N1 vaccine. We here report our development of a multiple-clade H5N1 influenza vaccine tested for immunogenicity and efficacy to confer cross-protection in an animal model.Methodology/Principal FindingsMice received two doses of influenza split vaccine with oil-in-water emulsion adjuvant SP01 by intranasal administration separated by two weeks. Single vaccines (3 µg HA per dose) included rg-A/Vietnam/1203/2004(Clade 1), rg-A/Indonesia/05/2005(Clade 2.1), and rg-A/Anhui/1/2005(Clade 2.3.4). The trivalent vaccine contained 1 µg HA per dose of each single vaccine. Importantly, complete cross-protection was observed in mice immunized using trivalent vaccine with oil-in-water emulsion adjuvant SP01 that was subsequently challenged with the lethal A/OT/SZ/097/03 influenza strain (Clade 0), whereas only the survival rate was up to 60% in single A/Anhui/1/2005 vaccine group.Conclusion/SignificanceOur findings demonstrated that the multiple-clade H5N1 influenza vaccine was able to elicit a cross-protective immune response to heterologous HPAI H5N1 virus, thus giving rise to a broadly cross-reactive vaccine to potential prevention use ahead of the strain-specific pandemic influenza vaccine in the event of an HPAI H5N1 influenza outbreak. Also, the multiple-clade adjuvanted vaccine could be useful in allowing timely initiation of vaccination against unknown pandemic virus.

Seroprevalence of Antibodies against Highly Pathogenic Avian Influenza A (H5N1) Virus among Poultry Workers in Bangladesh, 2009

“…First, low titers may indicate cross reactive antibodies from a previous influenza A virus infection with a different subtype rather than the presence of HPAI H5N1 virus-specific neutralizing antibodies [11,13]. Single or multiple-clade H5N1 influenza vaccines can generate cross-clade neutralizing antibodies in humans and mice [22,23]. Nevertheless, only HPAI H5N1 clade 2.2.2 viruses were identified among domestic poultry in Bangladesh during 2007–2009 [1].…”

Influenza B-Cells Protective Epitope Characterization: A Passkey for the Rational Design of New Broad-Range Anti-Influenza Vaccines

“…The currently circulating H5N1 isolates that have infected humans can be grouped in four different clades (1.1, 2.1.3.2, 2.2.1 and 2.3.2.1) (WHO report February 2012) [91]. The divergence between different clades and subclades can correlate with a different antigenic pattern allowing the viral escape from the selective pressure of neutralizing antibodies directed against another antigenic group [19]. Several H5N1 isolates, belonging to different clades, have been identified as putative strains to be included in a possible pre-pandemic vaccine [91].…”

“…To overcome the limitations of the current vaccinal approaches, different strategies for the development of novel vaccinal strategies have been proposed [5,7,17,18,19,20,21,22]. A pivotal role in the rational design of novel broadly protective approaches can be played by the fine definition of B-cell epitopes on influenza hemagglutinin (HA), widely shared among phylogenetically highly divergent influenza subtypes.…”

Monoclonal Antibody Targeting Neutralizing Epitope on H5N1 Influenza Virus of Clade 1 and 0 for Specific H5 Quantification

“…The H5N1 influenza viruses are currently divisible into 10 clades (0 to 9) on the basis of phylogenetic analysis of their hemagglutinin (HA) genes that have evolved in the A/Goose/Guangdong/96-like H5N1 lineage (Clade 0) [6]. Clade 0 includes all the early progenitors which are predominately strains in 1996–2002 from Hong Kong (HK) and China, while clade 1 includes human and bird isolates from Vietnam, Thailand, and Cambodia and bird isolates from Laos and Malaysia [7]. The human isolate A/VietNam/1203/04 (H5N1) from the 2004 outbreak was identified as the most pathogenic isolate in Clade 1.0 [8, 9].…”