Mucosal immunization with a candidate universal influenza vaccine reduces transmission to unvaccinated contacts in a mouse model

Tuesday, October 09, 2012 — Poster Session I
1:00 p.m. – 3:00 p.m	Natcher Conference Center, Building 45	FDA/CBER	INFECTDIS-4

Authors

• G.E. Price
• C-Y. Lo
• J.A. Misplon
• S.L. Epstein

Abstract

Pandemic influenza is a major public health concern. We have previously demonstrated that immunization targeting viral antigens nucleoprotein (NP) and Matrix 2 (M2) conserved between all influenza virus strains and subtypes does not prevent infection, but can protect from morbidity and mortality. Such vaccines could be used early in a pandemic when strain-matched vaccines are unavailable. Virus titers in the respiratory tract are significantly reduced in vaccinated animals, so we hypothesized that such immunization may reduce virus transmission from vaccinated, infected animals. Ferrets and guinea pigs are currently used as model systems to study influenza virus transmission, but use of these models is limited by cost and lack of immunological reagents. Using an outbred mouse model for influenza virus transmission, we demonstrate that immunization with recombinant adenovirus vectors expressing NP and M2 induces antibody and T cell responses in the respiratory tract, and that immunization reduces virus levels in the respiratory tract resulting from challenge infection. Further, transmission of virus to co-housed, unimmunized mice is significantly reduced in comparison to controls. These findings have broad implications for the impact of conserved antigen vaccines, not only in protecting the vaccinated individual but also in protecting others by reducing influenza virus transmission.

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