Potency determination of inactivated H7 influenza vaccines using monoclonal antibody‐based ELISA and biolayer interferometry assays

Abstract

BackgroundThe single radial immunodiffusion (SRID) assay, the accepted method for determining potency of inactivated influenza vaccines, measures an immunogenic form of the influenza hemagglutinin. Nevertheless, alternative methods for measuring vaccine potency have been explored to address some of the weaknesses of the SRID assay, including limited sensitivity and the requirement for large amounts of standardized reagents. Monoclonal antibody (mAb)‐based potency assays also have the ability to detect and measure relevant immunogenic forms of HA.ObjectivesThe objective of this study was to continue evaluation of mAb‐based alternative methods for measuring the potency of inactivated influenza vaccines, focusing on A(H7N9) pandemic influenza vaccines.MethodsSeveral murine mAbs that recognize different epitopes on the H7 hemagglutinin (HA) were identified and characterized. These mAbs were evaluated in both a mAb‐capture ELISA and a mAb‐based biolayer interferometry (BLI) assay.ResultsResults indicated that potency of inactivated A(H7N9) vaccines, including vaccine samples that were stressed by heat treatment, measured by either alternative method correlated well with potency determined by the traditional SRID potency assay.ConclusionsThe availability of multiple H7 mAbs, directed to different HA epitopes, provides needed redundancy in the potency analysis as A(H7N9) viruses continue to evolve antigenically and suggests the importance of having a broad, well‐characterized panel of mAbs available for development of vaccines against influenza strains with pandemic potential. In addition, the results highlight the potential of mAb‐based platform such as ELISA and BLI for development as alternative methods for determining the potency of inactivated influenza vaccines.

Highly pathogenic avian influenza A/Guangdong/17SF003/2016 is immunogenic and induces cross-protection against antigenically divergent H7N9 viruses

“…Neutralizing mAbs 1E9, 5A6, and 7B5 target distinct epitopes located in the globular head of H7 HA (Fig. 7a, b ) 17 , 18 . Antibodies elicited by adjuvanted GD/16 eHA exhibited higher competitive capacity against mAb 1E9 than those induced by adjuvanted SH/2 or HK/125 eHA for HA binding (Fig.…”

“…Compared to adjuvanted SH/2 eHA, immunization of adjuvanted GD/16 eHA yielded better antibody quality by showing stronger competition with H7 mAbs for HA binding. 1E9, 5A6 and 7B5 are three neutralizing mAbs raised against SH/2 HA 17 , 18 . 1E9 and 5A6 recognize epitopes in the vicinity of HA antigenic site A, while 7B5 recognizes the epitope in antigenic site B, which is close to the receptor binding site 18 .…”

“…1E9, 5A6 and 7B5 are three neutralizing mAbs raised against SH/2 HA 17 , 18 . 1E9 and 5A6 recognize epitopes in the vicinity of HA antigenic site A, while 7B5 recognizes the epitope in antigenic site B, which is close to the receptor binding site 18 . Passive transfer of 5A6 protected recipient mice from SH/2 CVV challenge, while 7B5 and 1E9 were also found to recognize HAs of HK/125 and GD/16 18 .…”

Development and optimized pairing of mouse monoclonal antibodies for detecting hemagglutinin in novel H7 subtype influenza viruses

“…Initially, the organization recommended using the A/Anhui/1/2013 (H7N9) or A/Shanghai/2/2013 (H7N9) for a candidate vaccine virus in 2013 and then updated their report to A/ Guangdong/17SF003/2016 (H7N9) or A/Hunan/02650/2016 (H7N9) in 2017. A capture ELISA with mAbs against H7 HA was recently developed to quantify the HA of inactivated influenza vaccine A/Shanghai/2/2013 (H7N9) (Vasudevan et al, 2018). The five mAbs produced in our study and the matched pair 1C4/HRP-2D7 sandwich ELISA may be further developed for the characterization and quantification of HA antigen in developing vaccines against H7N9.…”

“…Compared with polyclonal antibodies, the mAb-based immunoassays owned the advantages of stability and specificity, and they may be exploited for diagnostic applications and other research. Although several studies on mAbs against avian influenza H7N9 HA have been reported (Yang et al, 2010;Malik et al, 2016;Schmeisser et al, 2015 a few focused on the neutralization effect (Malik et al, 2016, Schmeisser et al, 2015, Stadlbauer et al, 2018, and most of the diagnostic applications of the mAbs were derived from avian H7 protein prior to the novel influenza A (H7N9) virus outbreak (Vasudevan et al, 2018;Yang et al, 2010). In this study, the HA derived from novel H7 subtype influenza (A/Anhui/1/2013, H7N9) was used as immunogen for the mAb development.…”