Analysis of a Therapeutic Antibody Cocktail Reveals Determinants for Cooperative and Broad Ebolavirus Neutralization

Abstract

Graphical AbstractHighlights d Human mAbs of two epitope specificities bind cooperatively to the ebolavirus GP d Cooperativity is mediated by a mAb that enhances binding to a vulnerable GP epitope d A two-mAb cocktail exhibits enhanced potency against heterologous ebolaviruses d Two 30 mg/kg doses of the cocktail fully protected nonhuman primates (NHPs) challenged with EBOV SUMMARY Structural principles underlying the composition of protective antiviral monoclonal antibody (mAb) cocktails are poorly defined. Here, we exploited antibody cooperativity to develop a therapeutic mAb cocktail against Ebola virus. We systematically analyzed the antibody repertoire in human survivors and identified a pair of potently neutralizing mAbs that cooperatively bound to the ebolavirus glycoprotein (GP). High-resolution structures revealed that in a twoantibody cocktail, molecular mimicry was a major feature of mAb-GP interactions. Broadly neutralizing mAb rEBOV-520 targeted a conserved epitope on the GP base region. mAb rEBOV-548 bound to a glycan cap epitope, possessed neutralizing and Fc-mediated effector function activities, and potentiated neutralization by rEBOV-520. Remodeling of the glycan cap structures by the cocktail enabled enhanced GP binding and virus neutralization. The cocktail demonstrated resistance to virus escape and protected non-human primates (NHPs) against Ebola virus disease. These data illuminate structural principles of antibody cooperativity with implications for development of antiviral immunotherapeutics.

Complete mapping of mutations to the SARS-CoV-2 spike receptor-binding domain that escape antibody recognition

“…Such viruses provide a facile system to select for spike mutations that evade antibody neutralization ( Case et al, 2020 ; Dieterle et al, 2020 ; Weisblum et al, 2020 ). We chose five potently neutralizing antibodies (IC 50 values ranged from 15 to 150 ng/mL), and used a high-throughput quantitative real-time cell analysis assay ( Gilchuk et al, 2020a , 2020b ) to select viral mutants that could escape each individual antibody at a concentration of 5 μg/mL, performing between 16 and 56 individual replicates for each antibody ( Figure 6A and S6A , B , C ). For four of the five antibodies, this process selected viral variants that we confirmed resisted neutralization by 10 μg/mL of the antibody used for the selection ( Figure 6A ).…”

“…To screen for escape mutations selected in the presence of individual antibodies or antibody cocktails, we used a real-time cell analysis assay (RTCA) and xCELLigence RTCA MP Analyzer (ACEA Biosciences Inc.) with modification of previously described assays (Gilchuk et al, 2020a;Weisblum et al, 2020) . Fifty (50) μL of cell culture medium (DMEM supplemented with 2% FBS) was added to each well of a 96-well E-plate to obtain a background reading.…”

Structural Biology of Influenza Hemagglutinin: An Amaranthine Adventure

“…Similarly, escape mutants to RBS bnAbs can be even more readily isolated [157,158]. Notwithstanding, studies in Zika virus, Ebola virus, HBV, and SARS-CoV-2 have shown that use of a well-designed antibody cocktail can minimize the emergence of escape mutants [159][160][161][162]. Thus, a universal influenza vaccine may need to induce a polyclonal response that targets both the RBS and stem domain to prevent or mitigate against escape.…”

Single-component multilayered self-assembling nanoparticles presenting rationally designed glycoprotein trimers as Ebola virus vaccines

“…As a result, large panels of NAbs were isolated from human 59 survivors, vaccinated humans, and immunized animals (12,(34)(35)(36)(37)(38)(39). Crystallography (40)(41)(42)(43) and 60 electron microscopy (EM) (44)(45)(46)(47) have revealed multiple sites of vulnerability on EBOV GP. A 61 recent study of 171 monoclonal antibodies (mAbs) defined eight classes of epitopes (48), six of which can be recognized by broadly neutralizing antibodies (bNAbs) (9).…”