A Virus-Like Particle That Elicits Cross-Reactive Antibodies to the Conserved Stem of Influenza Virus Hemagglutinin

Abstract

The discovery of broadly neutralizing antibodies that recognize highly conserved epitopes in the membrane-proximal region of influenza virus hemagglutinin (HA) has revitalized efforts to develop a universal influenza virus vaccine. This effort will likely require novel immunogens that contain these epitopes but lack the variable and immunodominant epitopes located in the globular head of HA. As a first step toward developing such an immunogen, we investigated whether the 20-residue A-helix of the HA2 chain that forms the major component of the epitope of broadly neutralizing antibodies CR6261, F10, and others is sufficient by itself to elicit antibodies with similarly broad antiviral activity. Here, we report the multivalent display of the A-helix on icosahedral virus-like particles (VLPs) derived from the capsid of Flock House virus. Mice immunized with VLPs displaying 180 copies/particle of the A-helix produced antibodies that recognized trimeric HA and the elicited antibodies had binding characteristics similar to those of CR6261 and F10: they recognized multiple HA subtypes from group 1 but not from group 2. However, the anti-A-helix antibodies did not neutralize influenza virus. These results indicate that further engineering of the transplanted peptide is required and that display of additional regions of the epitope may be necessary to achieve protection.

Sequential Infection in Ferrets with Antigenically Distinct Seasonal H1N1 Influenza Viruses Boosts Hemagglutinin Stalk-Specific Antibodies

“…A variety of approaches for eliciting HA stalkspecific antibody responses have been evaluated in animal models with various degrees of success (43,(48)(49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60). Collectively, these approaches aim to elicit HA stalk-specific responses through tactics that subvert HA globular head immunodominance.…”

Pan-ebolavirus and Pan-filovirus Mouse Monoclonal Antibodies: Protection against Ebola and Sudan Viruses

“…Epitopes conserved across filovirus species may not be immunodominant, and the B cell response is likely dominated by species-restricted epitopes during natural infection, which always involves a single species. This is reminiscent of antibodies to subdominant, broadly neutralizing, epitopes within the stem region of influenza virus hemagglutinin that are rarely induced during seasonal infections and that require special immunogen design or prime-boost regimens to be effectively elicited (42)(43)(44)(45). This is the first report of a single antibody (m8C4) to exhibit neutralization and protective efficacy against two different filovirus species.…”

Engineering of virus-like particles for alternative vaccine candidate targeting a hypervariable peptide antigen element

“…Two approaches to overcome these problems are: (i) the use of the larger domains from the pathogens containing selected peptide antigens but lacking other non-protective and undesirable antigens or domains; and (ii) the presentation of peptide antigens to unrelated carrier proteins for conformational stability (Kulp and Schief 2013). Examples of carrier proteins are: virus-like particles (VLPs) , Schneemann et al 2012, green fluorescence protein (Abedi et al 1998), cholera toxin B subunit (Totrov et al 2010), and selfassembling protein nanoparticles (Wahome et al 2012). …”

“…Nevertheless, antibodies induced against the grafted epitope are not effective for neutralisation (Ofek et al 2010, Ofek et al 2004. The approach has also been used for the Helix A epitope from HA2 of the influenza A virus (Schneemann et al 2012), and the motavizumab epitope from the Respiratory syncytial virus (McLellan et al 2011). …”

“…Murine leukaemia virus (MLV) gag particles have been used to display genetically fused HA and NA of an influenza virus using mammalian (Szécsi et al 2006) or insect cell ) expression systems. Similarly, gag VLPs have been used to display a headless HA protein of influenza (Steel et al 2010) and Flock House virus (FHV) VLPs have been used to display Helix A from the HA2 influenza virus (Schneemann et al 2012). In addition, studies have displayed peptide antigens from the M2 protein on VLPs from murine polyomavirus VP1 protein and HBcAg (De Filette et al 2006) via genetic fusion.…”