The Deleterious Effects of Shiga Toxin Type 2 Are Neutralized In Vitro by FabF8:Stx2 Recombinant Monoclonal Antibody
Daniela Luz,
Fernando D. Gómez,
Raíssa L. Ferreira,
Bruna S. Melo,
Beatriz E. C. Guth,
Wagner Quintilio,
Ana Maria Moro,
Agostina Presta,
Flavia Sacerdoti,
Cristina Ibarra,
Gang Chen,
Sachdev S. Sidhu,
María Marta Amaral,
Roxane M. F. Piazza
Affiliations
Daniela Luz
Laboratório de Bacteriologia, Instituto Butantan, Sao Paulo 05503-900, Brazil
Fernando D. Gómez
Laboratorio de Fisiopatogenia, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
Raíssa L. Ferreira
Laboratório de Bacteriologia, Instituto Butantan, Sao Paulo 05503-900, Brazil
Bruna S. Melo
Laboratório de Bacteriologia, Instituto Butantan, Sao Paulo 05503-900, Brazil
Beatriz E. C. Guth
Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal de Sāo Paulo, Sao Paulo 04023-062, Brazil
Wagner Quintilio
Laboratório de Biofármacos, Instituto Butantan, Sao Paulo 05503-900, Brazil
Ana Maria Moro
Laboratório de Biofármacos, Instituto Butantan, Sao Paulo 05503-900, Brazil
Agostina Presta
Laboratorio de Fisiopatogenia, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
Flavia Sacerdoti
Laboratorio de Fisiopatogenia, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
Cristina Ibarra
Laboratorio de Fisiopatogenia, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
Gang Chen
Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, OT M5S 3E1, Canada
Sachdev S. Sidhu
Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, OT M5S 3E1, Canada
María Marta Amaral
Laboratorio de Fisiopatogenia, Instituto de Fisiología y Biofísica Bernardo Houssay (IFIBIO Houssay-CONICET), Departamento de Fisiología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires 1121, Argentina
Roxane M. F. Piazza
Laboratório de Bacteriologia, Instituto Butantan, Sao Paulo 05503-900, Brazil
Hemolytic Uremic Syndrome (HUS) associated with Shiga-toxigenic Escherichia coli (STEC) infections is the principal cause of acute renal injury in pediatric age groups. Shiga toxin type 2 (Stx2) has in vitro cytotoxic effects on kidney cells, including human glomerular endothelial (HGEC) and Vero cells. Neither a licensed vaccine nor effective therapy for HUS is available for humans. Recombinant antibodies against Stx2, produced in bacteria, appeared as the utmost tool to prevent HUS. Therefore, in this work, a recombinant FabF8:Stx2 was selected from a human Fab antibody library by phage display, characterized, and analyzed for its ability to neutralize the Stx activity from different STEC-Stx2 and Stx1/Stx2 producing strains in a gold standard Vero cell assay, and the Stx2 cytotoxic effects on primary cultures of HGEC. This recombinant Fab showed a dissociation constant of 13.8 nM and a half maximum effective concentration (EC50) of 160 ng/mL to Stx2. Additionally, FabF8:Stx2 neutralized, in different percentages, the cytotoxic effects of Stx2 and Stx1/2 from different STEC strains on Vero cells. Moreover, it significantly prevented the deleterious effects of Stx2 in a dose-dependent manner (up to 83%) in HGEC and protected this cell up to 90% from apoptosis and necrosis. Therefore, this novel and simple anti-Stx2 biomolecule will allow further investigation as a new therapeutic option that could improve STEC and HUS patient outcomes.
