[Source: Proceedings of the National Academy of Sciences of the United States of America, full page: (LINK). Abstract, edited.]
Antibody-dependent enhancement of influenza disease promoted by increase in hemagglutinin stem flexibility and virus fusion kinetics
Katie L. Winarski, Juanjie Tang, Laura Klenow, Jeehyun Lee, Elizabeth M. Coyle, Jody Manischewitz, Hannah L. Turner, Kazuyo Takeda, Andrew B. Ward, Hana Golding, and Surender Khurana
PNAS first published July 11, 2019 / DOI: https://doi.org/10.1073/pnas.1821317116
Edited by Robert G. Webster, St. Jude Children’s Research Hospital, Memphis, TN, and approved June 19, 2019 (received for review December 14, 2018)
Next-generation influenza vaccines and broadly neutralizing antibodies (bNAbs) are in clinical development. Some of these do not block virus–receptor interactions and thus are predicted to provide protection via alternative mechanisms at the postentry stage or use Fc-dependent mechanisms. Nonneutralizing antibodies have the potential to mediate enhancement of respiratory disease (ERD). Our study describes ADE with two different functional MAbs that destabilized HA stem domain, increased influenza virus fusion kinetics, and led to enhanced lung pathology and ERD in a dose-dependent manner in a mice model. This study underlines careful preclinical evaluation of next-generation influenza vaccines or antibody-based therapeutics that do not block influenza virus receptor binding.
Several next-generation (universal) influenza vaccines and broadly neutralizing antibodies (bNAbs) are in clinical development. Some of these mediate inhibitions of virus replication at the postentry stage or use Fc-dependent mechanisms. Nonneutralizing antibodies have the potential to mediate enhancement of viral infection or disease. In the current study, two monoclonal antibodies (MAbs) 72/8 and 69/1, enhanced respiratory disease (ERD) in mice following H3N2 virus challenge by demonstrating increased lung pathology and changes in lung cytokine/chemokine levels. MAb 78/2 caused changes in the lung viral loads in a dose-dependent manner. Both MAbs increased HA sensitivity to trypsin cleavage at a higher pH range, suggesting MAb-induced conformational changes. pHrodo-labeled virus particles’ entry and residence time in the endocytic compartment were tracked during infection of Madin-Darby canine kidney (MDCK) cells. Both MAbs reduced H3N2 virus residence time in the endocytic pathway, suggesting faster virus fusion kinetics. Structurally, 78/2 and 69/1 Fabs bound the globular head or base of the head domain of influenza hemagglutinin (HA), respectively, and induced destabilization of the HA stem domain. Together, this study describes Mab-induced destabilization of the influenza HA stem domain, faster kinetics of influenza virus fusion, and ERD in vivo. The in vivo animal model and in vitro assays described could augment preclinical safety evaluation of antibodies and next-generation influenza vaccines that generate antibodies which do not block influenza virus–receptor interaction.
universal – stem – influenza – antibody-dependent enhancement (ADE) – vaccine
1 K.L.W., J.T., and L.K. contributed equally to this work.
2 To whom correspondence may be addressed. Email: Surender.Khurana@fda.hhs.gov.
Author contributions: S.K. designed research; K.L.W., J.T., L.K., J.L., E.M.C., J.M., H.L.T., K.T., A.B.W., and S.K. performed research; K.L.W., J.T., L.K., H.L.T., K.T., A.B.W., and S.K. analyzed data; and A.B.W., H.G., and S.K. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1821317116/-/DCSupplemental.
Published under the PNAS license.
Keywords: Influenza A; Monoclonal antibodies; Vaccines; Antibody Dependent Enhancement.