Characterisation of anti- Escherichia coli Monoclonal Antibodies for Use in Diagnostic Assays

Abstract

A number of monoclonal antibodies were produced against Escherichia coli and two of them were chosen for further study. Antibody 2D1 reacted with all 34 E. coli strains assessed but not with a variety of other bacterial strains, including 45 Salmonella. Antibody 4E1 was more broadly reactive and bound to all E. coli and Salmonella strains tested as well as some species of Enterobacteriaceae. The isotype for 2D1 was found to be IgG2a and for 4E1, IgG2b, both with kappa light chains. The 2D1 antibody was further characterised, and shown to identify a heat modifiable outer membrane protein of E. coli. The effect of temperature, detergent and 2-mercaptoethanol was assessed on exposing the 2D1 epitope using SDS-PAGE and immunoblotting. 4E1 binding was investigated with rough mutants and the antibody was found to identify an inner core, heptose-associated, structure.

Keywords:

• e. Coli
• Monoclonal Antibodies
• Diagnostics