A homogeneous immunological detection system for soman using the in vitro protection of acetylcholinesterase by a monoclonal antibody.

In this study a monoclonal antibody (MAb) based soman detection system was investigated. Since the MAb F71D7 recognizes the pinacolyl group of soman, non-toxic soman analogues are also detected when using an indirect competitive ELISA. This can lead to falsely positive results. The toxic effect of soman is, however, independent of the pinacolyl group. In the described homogeneous enzyme immunoassay (EIA), the inhibitory effect of soman on acetylcholinesterase (AChE) was combined with its specific binding to the MAb F71D7 in order to minimize false positive results and enhance the specificity of the detection system. In this rapid EIA no incubation or washing steps are necessary, so only time for pipetting and reaction have to be considered. Soman could be detected in concentrations of 1.6-25 nM using the EIA. This corresponds to 8 pg soman per 25 microliters sample and means that compared to other ELISA systems, besides enhanced specificity, the limit of detection could be improved by 3 orders of magnitude.