Obtainment of recombinant antibody fragments (scFv and Fab) selected by Phage Display against heat-labile (LT) and heat-stable (ST) toxins produced by enterotoxigenic Escherichia coli

• Grant number: 22/13313-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2023
• End date: December 31, 2023
• Field of knowledge: Health Sciences - Collective Health - Public Health
• Principal Investigator: Daniela Luz Hessel da Cunha
• Grantee: Yuuki Yamamoto
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Diarrheal disease is one of the main public health problems worldwide, causing about 1.5 million deaths annually in children under five years of age, and about 30 to 40% of episodes of acute diarrhea in the world are caused by diarrheagenic Escherichia coli, with emphasis on the pathotype responsible for acute diarrhea/traveller's diarrhea, enterotoxigenic E. coli (ETEC). ETEC produces the thermostable (ST) and thermolabile (LT) toxins. These toxins are the main virulence factors, therefore, excellent targets for the diagnosis of diarrhea caused by these pathogens and for the therapy of intoxication. Among the best tools for both the development of immunosorological tests and for neutralization therapy, antibodies stand out. Based on recombinant DNA technology and the award-winning Phage Display technique, it is possible to develop recombinant antibodies more quickly and at low cost, such as scFv and Fab fragments that can even be produced in bacteria, an advance over monoclonal strains produced by hybridomas that require time and skilled labor to obtain. Over the years, our research group at the Bacteriology Laboratory of the Instituto Butantan has successfully obtained antibodies, including recombinant ones, and standardized diagnostic methods for the epidemiologically important pathotypes of diarrheagenic Escherichia coli. In this context, this project aims to obtain high-affinity fragments against the LT and ST toxins of ETEC using the Phage Display technique, which after being purified and characterized will be tested as diagnostic and therapeutic tools for these pathogens.