Elicitation of Broadly Protective Antibodies following Infection with Influenza Viruses Expressing H1N1 Computationally Optimized Broadly Reactive Hemagglutinin Antigens

Abstract

Influenza viruses represent a threat to the world population. The currently available standard of care influenza vaccines are offered for each influenza season to prevent infection and spread of influenza viruses. Current vaccine formulations rely on using wild-type Ags, including the hemagglutinin (HA) and neuraminidase (NA) proteins as the primary immune targets of the vaccine. However, vaccine effectiveness varies from season to season, ranging from 10 to 75% depending on season and on age group studied. To improve rates of vaccine effectiveness, a new generation of computationally optimized broadly reactive Ags (COBRA)-based vaccines have been developed as a next-generation influenza vaccine. In this report, mice were intranasally, i.p., or i.m. primed with reassortant influenza viruses expressing different H1N1 COBRA HA proteins. These mice were subsequently boosted i.p. or i.m. with the same viruses. Sera collected from mice that were intranasally infected and i.p. boosted with COBRA-based viruses had broad anti-HA IgG binding, hemagglutination inhibition, and neutralizing activity against a panel of seasonal and pandemic H1N1 viruses. Mice immunized with viruses expressing a seasonal or pandemic H1N1 HA protein had antisera that recognized fewer viruses in the panel. Overall, COBRA-based HA proteins displayed on the surface of a virus elicited a breadth of Abs that recognized and neutralized historical H1N1 strains as well as more contemporary H1N1 viruses. ImmunoHorizons, 2018, 2: 226-237.

Preexisting subtype immunodominance shapes memory B cell recall response to influenza vaccination

“…Full-length HA proteins were developed for each of the Fluozone 2016/17 quadrivalent vaccine components: H1N1, H3N2, Victoria-lineage, and Yamagata-lineage. Chimeric HA proteins were generated with the globular head portion of A/mallard/Sweden/81/2002 (A/H6N2) in the context of A/ California/07/2009 (A/H1N1 pan ) stem (cH6/1) or A/Anhui/1-YK/2013 (A/H7/N2) in the context of A/ Perth/16/2009 (A/H3N2) stem, as previously described (78,79). Correct stem conformation was validated by ELISA using CR6261 or CR8020 stem-directed monoclonal antibodies.…”

“…Correct stem conformation was validated by ELISA using CR6261 or CR8020 stem-directed monoclonal antibodies. WT and chimeric rHA proteins were expressed in EXPI293 cells and purified via a C-terminal histidine tag using HisTrap excel nickel-affinity chromatography columns (GE Healthcare Life Sciences) as previously described (79). Purified rHA proteins were dialyzed against PBS, and total protein concentration was adjusted to ~1 mg/mL after BCA estimation.…”

IgA Responses Following Recurrent Influenza Virus Vaccination

“…Full-length HA proteins were developed for each of the Fluzone TM influenza A vaccine components: A/California/7/2009 (H1N1), A/Texas/50/2012 (H3N2), A/Switzerland/9715293/ 2013 (H3N2), A/Hong Kong/4801/2014 (H3N2) as well as past H1N1 and H3N2 vaccine strains (Table S1). A chimeric HA protein was generated by cloning the head portion of A/mallard/Sweden/81/2002 (A/H6N2) on top of A/California/07/2009 (A/H1N1 pan ) stem region (cH6/1) (28,29). Correct stem conformation was validated by enzymelinked immunosorbent assay (ELISA) using FI6, CR6261 (Creative Biolabs, Shirley, NY, USA) and C179 (Takara Bio, Mountain View, CA, USA) stem-directed monoclonal antibodies (29,30).…”

“…A chimeric HA protein was generated by cloning the head portion of A/mallard/Sweden/81/2002 (A/H6N2) on top of A/California/07/2009 (A/H1N1 pan ) stem region (cH6/1) (28,29). Correct stem conformation was validated by enzymelinked immunosorbent assay (ELISA) using FI6, CR6261 (Creative Biolabs, Shirley, NY, USA) and C179 (Takara Bio, Mountain View, CA, USA) stem-directed monoclonal antibodies (29,30). Recombinant HA (rHA) proteins representing the wild type and chimeric amino acid sequence were expressed in EXPI293 cells and purified via a C-terminal histidine tag on HisTrap excel nickel-affinity chromatography columns (GE Healthcare Life Sciences, Marlborough, MA, USA) as previously described (29,30).…”

Recombinant Influenza Vaccines: Saviors to Overcome Immunodominance

“…This approach uses multiple rounds of consensus generation to aggregate HA epitopes of IAV from different time periods. Such vaccines elicit polyclonal B cell responses and was shown to protect within subtypes (116)(117)(118)(119)(120)(121)(122)(123). Combining several COBRA vaccines could confer heterosubtypic protection.…”