The aim of this project is to learn more about the mechanism of neutralization of cross-reactive immune responses to the influenza virus surface glycoproteins, hemagglutinin and neuraminidase, and to investigate the quantitative contribution of these mechanisms to protection. To approach this we will map the epitopes of a large panel of human (in collaboration with Project 2) and mouse cross-reactive anti-neuraminidase antibodies in order to define broadly neutralizing epitopes. Further, efforts will be made to characterize the quantitative contribution of different mechanisms of neutralization of a vast panel of broadly reactive antistalk and anti-neuraminidase monoclonal antibodies (of human and mouse origin, in collaboration with Project 2) and polyclonal sera. This work will involve in vivo imaging as well as a panel of assays that measure inhibition of viral entry/fusion, viral egress, hemagglutinin maturation, neuraminidase inhibition, complement activation and others (Project 3 will focus on antibody-dependent cell-mediated cytotoxicity). Finally, we use recombinant chimeric hemagglutinin and neuraminidase expressing influenza B viruses to study the impact of polyclonal anti-stalk and anti-neuraminidase responses on influenza virus pathogenesis and transmission in the mouse, guinea pig and ferret model.
Understanding mechanisms of broad neutralization of influenza viruses based on humoral responses against the influenza virus surface glycoproteins is essential for the establishment of new, more accurate correlates of protection and for the development of assays to measure them. It is important to investigate the potency and quantitative contribution of single mechanisms to protection in polyclonal sera as basis for rational vaccine design and information about broadly neutralizing epitopes on the influenza virus neuraminidase will greatly impact on the development of neuraminidase based vaccines. Addressing these points is crucial to set the stage for the development of broader and longer lasting influenza virus vaccines which would also enhance our pandemic preparedness against emerging viruses like H7N9.
|Wohlbold, Teddy John; Krammer, Florian (2014) In the shadow of hemagglutinin: a growing interest in influenza viral neuraminidase and its role as a vaccine antigen. Viruses 6:2465-94|
|Ellebedy, Ali H; Krammer, Florian; Li, Gui-Mei et al. (2014) Induction of broadly cross-reactive antibody responses to the influenza HA stem region following H5N1 vaccination in humans. Proc Natl Acad Sci U S A 111:13133-8|
|Tan, Gene S; Lee, Peter S; Hoffman, Ryan M B et al. (2014) Characterization of a broadly neutralizing monoclonal antibody that targets the fusion domain of group 2 influenza A virus hemagglutinin. J Virol 88:13580-92|
|Nachbagauer, Raffael; Wohlbold, Teddy John; Hirsh, Ariana et al. (2014) Induction of broadly reactive anti-hemagglutinin stalk antibodies by an H5N1 vaccine in humans. J Virol 88:13260-8|