Multiplex Immunoassays in the Development of Vaccines Against Enteric Pathogens

Bacterial enteric pathogens causing travelers diarrhea (TD) in developing countries include enterotoxigenic E. coli (50%), Camplyobacter jejuni, Shigella sonnei and Shigella flexneri, while Norovirus is a common viral cause. High risk regions for TD include areas where US service members are deployed. The rapid identification of immune responses to enteric pathogens would be advantageous to discovering potential vaccine candidates and defining exposures to enteric infections of interest. Enzyme linked immunosorbent assays (ELISA) are the current gold standard to measure serum antibody titers in response to enteric pathogens. However, ELISAs have significant limitations preventing their application in high-throughput screening of large sample numbers for multiple pathogens simultaneously. The difficulty of multiplexing ELISAs in a single well leads to increased usage of serum sample as well as reagents. Therefore, an assay is needed that can be multiplexed to detect several different pathogens in a single well and requires minimal technician time to perform. In this Phase I, Agave BioSystems demonstrated proof-of-concept for the use of flow cytometry microspheres in a multiplex assay to determine immunogenicity of candidate vaccines as well as prior pathogen exposure in blood. This novel multiplex microsphere-based assay will cover the most common causative pathogens of diarrhea.