Abstract
Shiga toxin (Stx)-producing Escherichia coli (STEC) causes bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Molecular structural analysis of Stx-neutralizing monoclonal antibody (mAb) will be helpful for development of therapeutics and prophylactics for STEC infection. In this study, we cloned the genes of Stx 1-neutralizing mAb, termed 5-5B from hybridoma cells by phage display system and characterized its recombinant Fab (rFab) fragment. 5-5B rFab fragment reacted with Stx1, but not with Stx2 and bovine serum albumin (BSA). It also showed the neutralizing activity against the cytotoxicity of Stx1. These results imply that 5-5B rFab fragment is functionally identical to parent mAb. The variable heavy (VH) and light domains were found to be highly homologous with the derived germ line sequences. As for VH domain, the complementarity determining regions (CDRs) showed higher replacement/substitution mutation ratio than that in the frame work regions. Among the regions, CDR2 showed the most frequent nucleotide and amino acid substitutions. These results suggest that heavy chain CDR2 may mainly be associated with the 5-5B function, that is neutralizing cytotoxicity of Stx1.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
