Delineation of B-cell Epitopes of Salmonella enterica serovar Typhi Hemolysin E: Potential antibody therapeutic target

Abstract

Hemolysin E (HlyE) is an immunogenic novel pore-forming toxin involved in the pathogenesis of typhoid fever. Thus, mapping of B-cell epitopes of Salmonella enterica serovar Typhi (S. Typhi) is critical to identify key immunogenic regions of HlyE. A random 20-mer peptide library was used for biopanning with enriched anti-HlyE polyclonal antibodies from typhoid patient sera. Bioinformatic tools were used to refine, analyze and map the enriched peptide sequences against the protein to identify the epitopes. The analysis identified both linear and conformational epitopes on the HlyE protein. The predicted linear GAAAGIVAG and conformational epitope PYSQESVLSADSQNQK were further validated against the pooled sera. The identified epitopes were then used to isolate epitope specific monoclonal antibodies by antibody phage display. Monoclonal scFv antibodies were enriched for both linear and conformational epitopes. Molecular docking was performed to elucidate the antigen-antibody interaction of the monoclonal antibodies against the epitopes on the HlyE monomer and oligomer structure. An in-depth view of the mechanistic and positional characteristics of the antibodies and epitope for HlyE was successfully accomplished by a combination of phage display and bioinformatic analysis. The predicted function and structure of the antibodies highlights the possibility of utilizing the antibodies as neutralizing agents for typhoid fever.

Multipathogen Analysis of IgA and IgG Antigen Specificity for Selected Pathogens in Milk Produced by Women From Diverse Geographical Regions: The INSPIRE Study

“…Toxins and lytic proteins were another strongly represented class of reactive proteins. Salmonella hemolysin E, a pore forming toxin with potential therapeutic antibody application, was reactive in LMICs and mostly nonreactive in HICs; but overall levels were low ( Figure 4A ) ( 72 ). ETEC accessory colonization factor YghJ, which has mucinolytic activity and used for intestinal colonization, was particularly high in the Peruvian and U.S.-California cohorts ( 69 ).…”

Generation and characterization of cross neutralizing human monoclonal antibody against 4 serotypes of dengue virus without enhancing activity

“…Several studies have been approved for successful utilization of random peptide phage display for finding specific epitope to several antiviral ( Xue et al, 2012 ; Zhao et al, 2012 ), and anti-flavivirus monoclonal antibody (MAb) ( Sun et al, 2011 ). This technique provides an economical and rapid approach for mapping antibody epitopes ( Zhang et al, 2006 ; Chin et al, 2017 ). We mapped the epitopes of our HuMAb to LXXXG which correspond to 107LFGKG111 located in the conserved N-terminal fusion loop of envelope domain II (EDII).…”

Understanding and Modulating Antibody Fine Specificity: Lessons from Combinatorial Biology

“…The Fc region of the selector antibody could select Fc-binding peptides not interacting with the paratope. Known TUPs can be excluded after sequencing [ 40 , 41 ], but more importantly, panning should be optimized to avoid nonspecific interactions and restrict selection to paratope binders.…”