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. 2018 Aug 9;36(33):5097-5103.
doi: 10.1016/j.vaccine.2018.06.053. Epub 2018 Jul 13.

Novel influenza vaccine M2SR protects against drifted H1N1 and H3N2 influenza virus challenge in ferrets with pre-existing immunity

Yasuko Hatta  1 , David Boltz  2 , Sally Sarawar  3 , Yoshihiro Kawaoka  4 , Gabriele Neumann  5 , Pamuk Bilsel  6
Affiliations

Novel influenza vaccine M2SR protects against drifted H1N1 and H3N2 influenza virus challenge in ferrets with pre-existing immunity

Yasuko Hatta et al. Vaccine. .

Abstract

Current influenza vaccines do not provide effective protection against heterologous influenza viruses. The ability of the novel M2SR influenza vaccine to protect against drifted influenza viruses was evaluated in naïve ferrets and in ferrets with pre-existing immunity to influenza. In naïve ferrets, M2SR provided similar protection against drifted challenge viruses as the comparator vaccine, FluMist®. However, in ferrets with pre-existing immunity, M2SR provided superior protection than FluMist in two model systems. In the first model, ferrets were infected with influenza A H1N1pdm and influenza B viruses to mimic the diverse influenza exposure in humans. The pre-infected ferrets, seropositive to H1N1pdm and influenza B but seronegative to H3N2, were then vaccinated with H3N2 M2SR or monovalent H3N2 FluMist virus (A/Brisbane/10/2007, clade 1) and challenged 6 weeks later with a drifted H3N2 virus (clade 3C.2a). Antibody titers to Brisbane/10/2007 were higher in M2SR vaccinated ferrets than in FluMist vaccinated ferrets in the pre-infected ferrets whereas the opposite was observed in naïve ferrets. After challenge with drifted H3N2 virus, M2SR provided superior protection than FluMist monovalent vaccine. In the second model, the impact of homologous pre-existing immunity upon vaccine-induced protection was evaluated. Ferrets, pre-infected with H1N1pdm virus, were vaccinated 90 days later with H1N1pdm M2SR or FluMist monovalent vaccine and challenged 6 weeks later with a pre-pandemic seasonal H1N1 virus, A/Brisbane/59/2007 (Bris59). While cross-reactive serum IgG antibodies against the Bris59 HA were detected after vaccination, anti-Bris59 hemagglutination inhibition antibodies were only detected post-challenge. M2SR provided better protection against Bris59 challenge than FluMist suggesting that homologous pre-existing immunity affected FluMist virus to a greater degree than M2SR. These results suggest that the single replication intranasal M2SR vaccine provides effective protection against drifted influenza A viruses not only in naïve ferrets but also in those with pre-existing immunity in contrast to FluMist viruses.

Keywords: Drifted; Hemagglutination inhibition; Heterosubtypic immunity; Intranasal; Live influenza; M2-deficient; Pre-existing immunity; Single replication.

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Conflict of interest statement

Conflict of interest statements: S.S. and D.B. have no conflicts of interest. G.N. and Y.K. are founders of FluGen. Y.H. and P.B. are employees of FluGen.

Figures

Figure 1
Figure 1. Serum antibody titers in naïve and pre-infected ferrets
Ferrets were infected with influenza A H1N1 and influenza B viruses to generate pre-existing immunity (pre-infected). Forty-five days later age-matched naive ferrets (filled symbols) and pre-infected ferrets (open symbols) were intranasally inoculated with H3N2 vaccine viruses Bris10 M2SR or FluMist-like (107 TCID50) or mock inoculated with PBS. Serum samples were collected before immunization (day -5) and after immunization (day 21 or day 35). A. Individual pre-vaccination serum IgG titers against recombinant HA of A/California/07/2009 (H1N1pdm), B/Brisbane/60/2007 (Victoria lineage), and B/Wisconsin/01/2010 (Yamagata lineage) were determined by ELISA (day -5). B. Individual serum IgG titers against recombinant HA of A/Brisbane/10/2007 (A/Bris10, H3N2) were measured by ELISA for pre-vaccination (day -5) and post-vaccination (day 35) time-points. Limit of detection is indicated by horizontal dashed line. C. Hemagglutination inhibition (HAI) titers against vaccine strain (A/Bris10, H3N2) were determined using 0.5% turkey RBC. Horizontal dash line is limit of detection (HAI = 10). In all panels, symbols indicate individual animals; bars indicate group mean with standard error. Vertical dashed line separates naïve and pre-infected groups. *** p<0.0001, Two-way ANOVA.
Figure 2
Figure 2. M2SR vaccine controls drifted H3N2 challenge virus in naïve and pre-infected ferrets
Bris10 (clade 1; H3N2) or mock vaccinated ferrets (in naïve and pre-infected groups) were challenged with drifted H3N2 strain, A/AK140 (clade 3c.2a) six weeks after vaccination. Weight loss was monitored for 12 days post-challenge. Nasal wash samples were collected on days 1, 3, 5, and 7 post-challenge. Virus loads in the samples were determination by 50% tissue culture infection (TCID50) method in MDCK cells. A. Weight loss in naïve-vaccine groups after challenge. B. Virus titers in nasal wash from naïve-vaccine animals after challenge. C. Weight loss in pre-infected vaccine ferrets after challenge. D. Virus titers in nasal wash in pre-infected ferrets after challenge. The detection limit of the TCID50 assay (horizontal dashed line) was 1.5 log10 TCID50/mL. Symbols are individual ferret and bars are mean titers with standard error for group at indicated time-point. *** p<0.0001, ** p=0.0001, # p<0.0008, * p<0.05; Two-way ANOVA.
Figure 3
Figure 3. Cross-reactive serum antibody responses in naïve and pre-infected ferrets
Ferrets were infected with A/California/07/2009 (H1N1pdm) virus to generate homologous pre-existing immunity in ferrets (pre-infected). Age-matched naïve ferrets (filled symbols) and A/CA07 (H1N1pdm) pre-infected ferrets (open symbols) were intranasally inoculated with CA07 M2SR or FluMist-like (107 TCID50) or mock immunized with PBS. Serum samples were collected before immunization (day -3) and after vaccine inoculations (day 21). Serum IgG titer against recombinant A/CA07 HA (A) and recombinant A/Bris59 HA (H1N1) (B) were measured by ELISA. Limit of detection is indicated by horizontal dashed line. Symbols indicate individual ferret titers; bars indicate group mean. *** p<0.0006, ** p<0.009; Two-way ANOVA.
Figure 4
Figure 4. M2SR vaccine controls drifted H1N1 virus challenge in naïve and pre-infected ferrets
Six weeks after vaccination, ferrets were challenged with drifted H1N1 strain, A/Brisbane/59/2007 (H1N1). Weight loss was monitored for 12 days post-challenge. Nasal wash samples were collected on days 1, 3, 5, and 7 post-challenge. Viral load was determined by 50% tissue culture infection (TCID50) in MDCK cells. A. Weight loss in naïve-vaccine groups after challenge. B. Virus titers in nasal wash from naïve-vaccine animals after challenge. C. Weight loss in pre-infected vaccine ferrets after challenge. D. Virus titers in nasal wash in pre-infected ferrets after challenge. The detection limit of the TCID50 assay (horizontal dashed line) was 1.5 log10 TCID50/mL. Symbols are individual ferrets and bars are group mean titers with standard error at indicated time-point. **** p<0.0001, ** p<0.005, * p<0.05; Two-way ANOVA.
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References

    1. Belongia EA, et al. Effectiveness of inactivated influenza vaccines varied substantially with antigenic match from the 2004–2005 season to the 2006–2007 season. J Infect Dis. 2009;199(2):159–67. - PubMed
    1. Zimmerman RK, et al. 2014–2015 Influenza Vaccine Effectiveness in the United States by Vaccine Type. Clin Infect Dis. 2016;63(12):1564–1573. - PMC - PubMed
    1. Paules CI, et al. Chasing Seasonal Influenza - The Need for a Universal Influenza Vaccine. N Engl J Med. 2018;378(1):7–9. - PubMed
    1. Sridhar S, Brokstad KA, Cox RJ. Influenza Vaccination Strategies: Comparing Inactivated and Live Attenuated Influenza Vaccines. Vaccines (Basel) 2015;3(2):373–89. - PMC - PubMed
    1. Eick AA, et al. Comparison of the trivalent live attenuated vs. inactivated influenza vaccines among U.S. military service members. Vaccine. 2009;27(27):3568–75. - PubMed

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