Evaluation of Monoclonal Antibody (IgG2bMAb) for Detection of Coproantigen from Experimentally Infected Rats with Strongyloides ratti

Abstract

Background and Aim: Highly sensitive and specific diagnostic assay for the detection of Strongyloides is needed due to the intermittent and low concentration of eggs, larvae and adult worms that can be found in a faecal specimen. In some cases, repeated sampling of the faecal specimen is required to obtain satisfactory and reliable results. The aim of the study is to develop and evaluates monoclonal antibody-based Sandwich ELISA for the detection of coproantigen associated with Strongyloides infection using S. ratti as a model. Place and Duration of Study:  Department of Medical Microbiology and Parasitology, Faculty of Medicine and Health Sciences, University Malaysia, Between September 2018 and   March 2019. Methodology: The monoclonal antibody was raised against a soluble antigen of the infective filariform larvae (iL3) of S. ratti. The monoclonal antibody produced (IgG2bMAb) was evaluated for cross-reactivity against homologous and heterologous helminth antigens such as excretory-secretory (ES), infective larvae (iL3) and coproantigen of S. ratti, adult worms of A. caninum, A. suum, T. canis and T. cati. Results: An IgG2bMAb was observed to react with 30 kDa proteins associated with all homologous antigen from iL3, ES and coproantigen of S. ratti and cross-reacted with one heterologous antigen from adult worm of A. caninum at the same molecular weight. There was no cross-reaction observed with other heterologous antigens from adult worms of T. canis, T. cati and A. suum. The sensitivity of IgG2bMAb for the detection of S. ratti was 85% in Sandwich ELISA. Cross- reaction was observed with hookworm antigen that caused by A. caninum in Western immunoblotting. Conclusion: The results indicated that IgG2b have an immunodiagnostic property as IgG2bMAb and was able to detect antigens from coproantigen related to S. ratti with 85% sensitivity based on Sandwich ELISA) even though cross-reaction was observed with A. caninum. These findings will be very useful to tackle many cases of multiple worms’ infections such as both strongyloidiasis and hookworm. Therefore, we recommend that further evaluation and study in the human area where multiple infections can be common should be carried out.