Study of the most efficient therapeutic formulation using recombinant Fab antibodies against Shiga toxins (Stx) in in vitro and in vivo models

• Grant number: 22/11989-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2024
• End date: July 31, 2026
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Daniela Luz Hessel da Cunha
• Grantee: Ariela de Oliveira Pedro Bom Guilherme
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Shiga toxins (Stx) produced by Shiga toxin-producing Escherichia coli (STEC) are the most potent cytotoxins of type AB5, found as two distinct types (Stx1 and Stx2) and subtypes, causing hemolytic uremic syndrome (HUS), characterized by thrombocytopenia, hemolytic anemia, and renal failure, which can cause death. The most indicated treatment against Stx-mediated HUS is the neutralization of toxicity, currently non-existent. Antibodies are promising therapeutic tools. Recombinant DNA technology has made it possible to develop therapeutic recombinant antibody fragments. Four promising Fab fragments against Stx (FabC11:Stx2, FabF8:Stx2, FabC8:Stx1, and FabB6:Stx1) expressed in bacteria were previously obtained. Despite being able to neutralize purified Stx, the Fabs had a neutralizing capacity ranging from 10 to 80% against toxins produced by STEC isolates, due to the presence of different types and concentrations of toxins produced by these isolates. In this scenario, the present project aims to determine, based on in-depth analyses in vitro and in vivo, the best therapeutic formulation against Shiga toxin (Stx), using different combinations of recombinant Fab antibody fragments against Stx1 and Stx2 toxins. , still, the project aims to standardize and establish a large-scale production of this formulation, to get as close as possible to a viable biopharmaceutical for the market. It is hoped that this project will be able to significantly advance towards a specific and effective treatment against STEC infection and its consequences.