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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Development and Characterization of Recombinant Antibody Fragments That Recognize and Neutralize In Vitro Stx2 Toxin from Shiga Toxin-Producing Escherichia coli

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Luz, Daniela [1] ; Chen, Gang ; Maranhao, Andrea Q. [2, 3] ; Rocha, Leticia B. [1] ; Sidhu, Sachdev ; Piazza, Roxane M. F. [1]
Total Authors: 6
[1] Inst Butantan, Lab Bacteriol, Sao Paulo - Brazil
[2] Univ Toronto, Banting & Best Dept Med Res, Terrence Donnelly Ctr Cellular & Biomol Res, Toronto, ON - Canada
[3] Univ Brasilia, Lab Imunol, Brasilia, DF - Brazil
Total Affiliations: 3
Document type: Journal article
Source: PLoS One; v. 10, n. 3 MAR 19 2015.
Web of Science Citations: 11

Background Stx toxin is a member of the AB(5) family of bacterial toxins: the active A subunit has N-glyco-sidase activity against 28S rRNA, resulting in inhibition of protein synthesis in eukaryotic cells, and the pentamer ligand B subunits (StxB) bind to globotria(tetra) osylceramide receptors (Gb3/Gb4) on the cell membrane. Shiga toxin-producing Escherichia coli strains (STEC) may produce Stx1 and/or Stx2 and variants. Strains carrying Stx2 are considered more virulent and related to the majority of outbreaks, besides being usually associated with hemolytic uremic syndrome in humans. The development of tools for the detection and/or neutralization of these toxins is a turning point for early diagnosis and therapeutics. Antibodies are an excellent paradigm for the design of high-affinity, protein-based binding reagents used for these purposes. Methods and Findings In this work, we developed two recombinant antibodies; scFv fragments from mouse hybridomas and Fab fragments by phage display technology using a human synthetic antibody library. Both fragments showed high binding affinity to Stx2, and they were able to bind specifically to the GKIEFSKYNEDDTF region of the Stx2 B subunit and to neutralize in vitro the cytotoxicity of the toxin up to 80%. Furthermore, the scFv fragments showed 79% sensitivity and 100% specificity in detecting STEC strains by ELISA. Conclusion In this work, we developed and characterized two recombinant antibodies against Stx2, as promising tools to be used in diagnosis or therapeutic approaches against STEC, and for the first time, we showed a human monovalent molecule, produced in bacteria, able to neutralize the cytotoxicity of Stx2 in vitro. (AU)

FAPESP's process: 13/03160-9 - New strategies for recombinant antibodies generation against Stx1 and Stx2 toxins produced by Shiga toxin-producing E. coli
Grantee:Daniela Luz Hessel da Cunha
Support type: Scholarships abroad - Research Internship - Doctorate
FAPESP's process: 10/20148-4 - Recombinant antibodies (scFv) against the EspB protein and Stx1, Stx2 toxins : preparation and characterization of these tools for the immunodiagnosis of enteropatogenic Escherichia coli (EPEC) and Shiga producing Escherichia coli (STEC)
Grantee:Daniela Luz Hessel da Cunha
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 11/12928-2 - New challenge for the diagnosis of diarrheagenic Escherichia coli: recombinant antibody obtention against different virulence factors
Grantee:Roxane Maria Fontes Piazza
Support type: Regular Research Grants