A mutation in the receptor binding site enhances infectivity of 2009 H1N1 influenza hemagglutinin pseudotypes without changing antigenicity
ABSTRACT The 2009 H1N1 pandemic highlights the need to better understand influenza A infectivity and antigenicity. Relative to other recent seasonal H1N1 influenza strains, the 2009 H1N1 virus grew less efficiently in eggs, which hindered efforts to rapidly supply vaccine. Using lentiviral pseudotypes bearing influenza hemagglutinin (HA-pseudotypes) we evaluated a glutamine to arginine mutation at position 223 (Q223R) and glycosylation at residue 276 in HA for their effects on infectivity and neutralization. Q223R emerged during propagation in eggs and lies in the receptor binding site. We found that the Q223R mutation greatly enhanced infectivity of HA-pseudotypes in human cells, which was further augmented by inclusion of the viral neuraminidase (NA) and M2 proteins. Loss of glycosylation at residue 276 did not alter infectivity. None of these modifications affected neutralization. These findings provide information for increasing 2009 H1N1HA-pseudotype titers without altering antigenicity and offer insights into receptor use.
Full-textDOI: · Available from: Zhiping Ye, Aug 27, 2015
- SourceAvailable from: Xudong Lin
[Show abstract] [Hide abstract]
- "Hemagglutinin inhibition assays performed with H1N1pdm (rNY1682) antisera showed viruses possessing either rNY1682 HA or FluMist HA had the same hemagglutinin inhibition titer (data not shown). This illustrates that these two viruses show equivalent cross neutralization and is consistent with previous reports indicating that these substitutions don't influence antigenicity of H1N1pdm viruses   . "
ABSTRACT: The licensed live attenuated influenza A vaccine (LAIV) in the United States is created by making a reassortant containing six internal genes from a cold-adapted master donor strain (ca A/AA/6/60) and two surface glycoprotein genes from a circulating/emerging strain (e.g., A/CA/7/09 for the 2009/2010 H1N1 pandemic). Technologies to rapidly create recombinant viruses directly from patient specimens were used to engineer alternative LAIV candidates that have genomes composed entirely of vRNAs from pandemic or seasonal strains. Multiple mutations involved in the temperature-sensitive (ts) phenotype of the ca A/AA/6/60 master donor strain were introduced into a 2009 H1N1 pandemic strain rA/New York/1682/2009 (rNY1682-WT) to create rNY1682-TS1, and additional mutations identified in other ts viruses were added to rNY1682-TS1 to create rNY1682-TS2. Both rNY1682-TS1 and rNY1682-TS2 replicated efficiently at 30°C and 33°C. However, rNY1682-TS1 was partially restricted, and rNY1682-TS2 was completely restricted at 39°C. Additionally, engineering the TS1 or TS2 mutations into a distantly related human seasonal H1N1 influenza A virus also resulted pronounced restriction of replication in vitro. Clinical symptoms and virus replication in the lungs of mice showed that although rNY1682-TS2 and the licensed FluMist(®)-H1N1pdm LAIV that was used to combat the 2009/2010 pandemic were similarly attenuated, the rNY1682-TS2 was more protective upon challenge with a virulent mutant of pandemic H1N1 virus or a heterologous H1N1 (A/PR/8/1934) virus. This study demonstrates that engineering key temperature sensitive mutations (PB1-K391E, D581G, A661T; PB2-P112S, N265S, N556D, Y658H) into the genomes of influenza A viruses attenuates divergent human virus lineages and provides an alternative strategy for the generation of LAIVs.Vaccine 03/2012; 30(24):3691-702. DOI:10.1016/j.vaccine.2012.03.025 · 3.49 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Pseudotyped viral particles are being used as safe surrogates to mimic the structure and surface of many viruses, including highly pathogenic viruses such as avian influenza H5N1, to investigate biological functions mediated by the envelope proteins derived from these viruses. The first part of this article evaluates and discusses the differences in the production and characterization of influenza pseudoparticles. The second part focuses on the applications that such a flexible tool can provide in modern influenza research, in particular in the fields of drug discovery, molecular biology and diagnosis.Expert Review of Anticancer Therapy 04/2011; 9(4):443-55. DOI:10.1586/eri.11.25 · 3.06 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Pandemic 2009 H1N1 influenza A virus (2009 H1N1) differs from H1N1 strains that circulated in the past 50 years, but resembles the A/New Jersey/1976 H1N1 strain used in the 1976 swine influenza vaccine. We investigated whether sera from persons immunized with the 1976 swine influenza or recent seasonal influenza vaccines, or both, neutralize 2009 H1N1. Using retroviral pseudovirions bearing hemagglutinins on their surface (HA-pseudotypes), we found that 77% of the sera collected in 1976 after immunization with the A/New Jersey/1976 H1N1 swine influenza vaccine neutralized 2009 H1N1. Forty five percent also neutralized A/New Caledonia/20/1999 H1N1, a strain used in seasonal influenza vaccines during the 2000/01-2006/07 seasons. Among adults aged 48-64 who received the swine influenza vaccine in 1976 and recent seasonal influenza vaccines during the 2004/05-2008/09 seasons, 83% had sera that neutralized 2009 H1N1. However, 68% of age-matched subjects who received the same seasonal influenza vaccines, but did not receive the 1976 swine influenza vaccine, also had sera that neutralized 2009 H1N1. Sera from both 1976 and contemporary cohorts frequently had cross-neutralizing antibodies to 2009 H1N1 and A/New Caledonia/20/1999 that mapped to hemagglutinin subunit 2 (HA2). A conservative mutation in HA2 corresponding to a residue in the A/Solomon Islands/3/2006 and A/Brisbane/59/2007 H1N1 strains that circulated in the 2006/07 and 2007/08 influenza seasons, respectively, abrogated this neutralization. These findings highlight a cross-neutralization determinant influenced by a point mutation in HA2 and suggest that HA2 may be evolving under direct or indirect immune pressure.PLoS Pathogens 06/2011; 7(6):e1002081. DOI:10.1371/journal.ppat.1002081 · 8.06 Impact Factor