Comparison of EBOV GP IgG antibody reactivity: Results from two immunoassays in the Democratic Republic of the Congo

Abstract

Ebola virus (EBOV) is a highly infectious pathogen, and its long-term consequences continue to be investigated. With its high fatality rate and potential for reinfection or latent infection, continued development of research tools is of utmost importance. Using a cohort (n = 503) of existing bio-banked specimens from the Democratic Republic of the Congo (DRC) two EBOV glycoprotein (GP) immunoglobulin G (IgG) antibody-detection assays were compared: the gold-standard Filovirus Animal Non-Clinical Group (FANG) and a Multiplex bead-based Immunoassay (MIA) with seven pan-filoviral targets. As not all immunoassays have been shown to detect a vaccine-induced immune response, and previous EBOV serosurveillance has been primarily conducted with singleplex technology, this MIA was assessed as an additional resource. Among the cohort, as sample seroreactivity increased, assay correlation increased (r²=0.80). Correlation was sustained among sub-populations of the cohort-in detecting natural immunity among survivors and vaccine-derived responses. Additionally, when results were binarized by seroreactivity, there was high correlation between the two assays (kappa=0.70) with 71 serodiscordant samples. These data indicate that the MIA is an apt alternative to the singleplex FANG assay in detecting relative seroreactivity and can be used as a potential tool for widespread pan-filovirus serosurveillance in the DRC and similar contexts.

Keywords: Democratic Republic of the Congo; EBOV GP; Immunoassays; Serosurveillance.