Identification and characterization of a neutralizing monoclonal antibody that provides complete protection against Yersinia pestis

Abstract

Yersinia pestis (Y. pestis) has caused an alarming number of deaths throughout recorded human history, and novel prophylactics and therapeutics are necessary given its potential as a bioweapon. Only one monoclonal antibody has been identified to date that provides complete protection against Y. pestis. Here, we describe a second novel murine monoclonal antibody (F2H5) that provided complete protection against Y. pestis 141 infection when administered prophylactically to Balb/c mice (100 μg intravenously). We humanized F2H5, characterized its ability to bind to the Y. pestis F1 protein and further characterized the neutralizing epitope using computational and experimental approaches. While Western blot results suggested a linear epitope, peptide mapping using ELISA failed to identify an epitope, suggesting a conformational epitope instead. We adopted a computational approach based on Residue Contact Frequency to predict the site of antigen-antibody interaction and defined the F2H5/F1 binding site computationally. Based on computational approach, we determined that residues G104E105N106 in F1 were critical to F2H5 binding and that CDRH2 and CDRH3 of F2H5 interacted with F1. Our results show that combining computational approach and experimental approach can effectively identify epitopes.

Yersinia pestis Antigen F1 but Not LcrV Induced Humoral and Cellular Immune Responses in Humans Immunized with Live Plague Vaccine—Comparison of Immunoinformatic and Immunological Approaches

“…This peptide corresponded to the terminal part of the leader amino-acid sequence, and this finding could explain the positive reactions in F1-ELISA with sera from nonimmune donors. Notably, all epitopes predicted and verified in our study generally corresponded to the F1 immunoreactive epitopes revealed early in animal models, suggesting their universal nature [18,20,[33][34][35][36]. Overall, the presence of many highly reactive epitopes within F1 could explain the high antigenic activity of this protein capable of generating the relevant specific B-cell response in vaccinees that exist for up to 50 years (observation period of our study), providing the persistence of anti-F1 antibodies for such a long period of time.…”

Potent neutralizing monoclonal antibodies against Ebola virus isolated from vaccinated donors

“…We then applied an optimized residue contact frequency (RCF) algorithm to analyze the top 101 conformations and obtain the score of each amino acid residue. 32 The amino acid residues ranked among the top 10 or 20 scores ( Figure S5) and located in the region previously delineated by truncated GPs were considered critical sites for binding. Finally, we mapped the possible epitopes of the seven nAbs on the GP trimer ( Figure 5b).…”

“…The structure of the mAb Fab-GP complex was predicted using a method based on our previous work. 32 Briefly, a homologous constructed model of mAb Fab and a structure of EBOV GP (PDB ID: 5KEL) were used for docking with a Dock Proteins protocol (ZDOCK) in Discovery Studio 4.5 (https://www. 3dsbiovia.com/products/collaborative-science/biovia-discoverystudio/).…”

Plague vaccine: recent progress and prospects

“…pestis 141 strain. 88 Collectively, it would be possible that mAbs specific to F1 or LcrV can be utilized as a fast-acting post-exposure treatment for humans against Y. pestis infection.…”