A Replication-Defective Influenza Virus Harboring H5 and H7 Hemagglutinins Provides Protection against H5N1 and H7N9 Infection in Mice.

Abstract

The recent highly pathogenic avian influenza (HPAI) H5N1 and H7N9 viruses have caused hundreds of human infections with high mortality rates. Although H5N1 and H7N9 viruses have been limited mainly to avian species, there is high potential for these viruses to acquire human-to-human transmission and initiate a pandemic. A highly safe and effective vaccine is needed to protect against a potential H5N1 or H7N9 influenza pandemic. Here, we report the generation and evaluation of two reassortant influenza viruses, PR8-H5-H7NA and PR8-H7-H5NA These viruses contain six internal segments from A/Puerto Rico/8/1934 (PR8), the HA segment from either A/Alberta/01/2014 (H5N1) [AB14 (H5N1)] or A/British Columbia/01/2015 (H7N9) [BC15 (H7N9)], and a chimeric NA segment with either the BC15 (H7N9) HA gene or the AB14 (H5N1) HA gene flanked by the NA packaging signals of PR8. These viruses expressed both H5 and H7 HAs in infected cells, replicated to high titers when exogenous NA was added to the culture medium in vitro, and were replication defective and nonvirulent when administered intranasally in mice. Moreover, intranasal vaccination with PR8-H5-H7NA elicited robust immune responses to both H5 and H7 viruses, conferring complete protection against both AB14 (H5N1) and BC15 (H7N9) challenges in mice. Conversely, vaccination with PR8-H7-H5NA only elicited robust immune responses toward the H7 virus, which conferred complete protection against BC15 (H7N9) but not against AB14 (H5N1) in mice. Therefore, PR8-H5-H7NA has strong potential to serve as a vaccine candidate against both H5 and H7 subtypes of influenza viruses.IMPORTANCE Avian influenza H5N1 and H7N9 viruses infected humans with high mortality rates. A highly safe and effective vaccine is needed to protect against a potential pandemic. We generated and evaluated two reassortant influenza viruses, PR8-H5-H7NA and PR8-H7-H5NA, as vaccine candidates. Each virus contains one type of HA in segment 4 and the other subtype of HA in segment 6, thereby expressing both H5 and H7 subtypes of the HA molecule. The replication of viruses is dependent on the addition of exogenous NA in cell culture and is replication defective in vivo Vaccination of PR8-H5-H7NA virus confers protection to both H5N1 and H7N9 virus challenge; conversely, vaccination of PR8-H7-H5NA provides protection only to H7N9 virus challenge. Our data revealed that when engineering such a virus, the H5 or H7 HA in segment 6 affects the immunogenicity. PR8-H5-H7NA has strong potential to serve as a vaccine candidate against both H5 and H7 subtypes of influenza viruses.

• Authors: Xingui Tian, Shelby Landreth, Yao Lu, Kannupriya Pandey, Yan Zhou
• Journal: Journal of virology (J Virol) Vol. 95 Issue 3 (01 13 2021) ISSN: 1098-5514 [Electronic] United States
• PMID: 33177192 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2021 American Society for Microbiology.

Chemical References

• Hemagglutinin Glycoproteins, Influenza Virus
• Influenza Vaccines
• Vaccines, Inactivated
• hemagglutinin, avian influenza A virus

Topics

• Animals
• Dogs
• Female
• Hemagglutinin Glycoproteins, Influenza Virus (genetics, immunology, metabolism)
• Influenza A Virus, H5N1 Subtype (immunology)
• Influenza A Virus, H7N9 Subtype (immunology)
• Influenza Vaccines (administration & dosage)
• Madin Darby Canine Kidney Cells
• Male
• Mice
• Mice, Inbred BALB C
• Orthomyxoviridae Infections (immunology, metabolism, prevention & control, virology)
• Vaccination
• Vaccines, Inactivated (administration & dosage)
• Virus Replication