Multiple-clade H5N1 influenza split vaccine elicits broad cross protection against lethal influenza virus challenge in mice by intranasal vaccination.

• Main Authors: Penghui Yang, Yueqiang Duan, Peirui Zhang, Zhiwei Li, Cheng Wang, Mei Dong, Chong Tang, Li Xing, Hongjing Gu, Zhongpeng Zhao, Xiufan Liu, Shaogeng Zhang, Xiliang Wang
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2012-01-01
• Series: PLoS ONE
• Online Access: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/22279575/pdf/?tool=EBI

<h4>Background</h4>The 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.<h4>Methodology/principal findings</h4>Mice 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.<h4>Conclusion/significance</h4>Our 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.