Case Studies |
Research & Development
The Opportunity
ProZyme, Inc, and Radix BioSolutions partnered to examine the effect of SAPE conjugate on commercial xMAP kits. Radix BioSolutions xMAP assays, one of which was observed to be sensitive to high background in high concentrations of SAPE conjugate and/or antigen.
The Challenge
In a multiplex, selecting the a reagent that provides optimal conditions for all analytes is often the most significant challenge. For these commercial kits a SAPE conjugate was needed that would not have reduced signal on the well-functioning assay but that would improve behavior of the sensitive assay to reduce the signal-to-noise ratio.
The enteric pathogens included a large number of related, but distinct organisms. Identification of the organisms had been based on antigenic or biochemical analysis. While this approach is effective, it may have failed to identify potential pathogens if they were antigenic variants or differed in metabolic pathways. An alternative approach to rapid detection and identification of pathogens is to develop methods that detect genes encoding virulence factors associated with a particular syndrome rather than detecting bacteria that may or may not have these virulence factors.
The Solution
With a wide range of conjugates and multiple lots of these conjugates available, a screening matrix was performed to compare the behavior of each, followed by varying concentrations of selected conjugates. High concentrations of antigens were used to screen the conjugates, as this is the condition under which one of the assays was failing.
The Results
The failing assay was found to be SAPE-conjugate-influenced and a specific lot of one conjugate was discovered to increase sensitivity of both assays by ½ log while reducing the signal-to-noise ratio of the poorly performing assay. This collaborative study with ProZyme, Inc. assisted both companies in understanding the importance of SAPE conjugate selection in assay development. At Radix BioSolutions this critical step has been integrated into the assay development process, and at ProZyme, Inc a sampler package of several conjugates is now offered to provide scientists developing xMAP assays with the tools useful for selecting the best conjugate for their needs.