Detection and quantification of microcystins (cyanobacterial hepatotoxins)with recombinant antibody fragments isolated from a naive human phage display library

Single-chain antibody fragments against the cyanobacterial hepatotoxin micr ocystin-LR were isolated from a naive human phage display library and expre ssed in Escherichia coli. In competition enzyme-linked immunosorbent assay (ELISA), the most sensitive antibody clone selected from the library detect ed free microcystin-LR with an IC50 value of 4 muM. It was found to cross r eact with three other microcystin variants - microcystin-RR, microcystin-LW and microcystin-LF - and detected microcystins in extracts of the cyanobac terium Microcystis aeruginosa, found to contain the toxins by high-performa nce liquid chromatography (HPLC). The quantification of microcystins in the se extracts by ELISA and HPLC showed good correlation. Although the antibod y isolated in this study was considerably less sensitive than the polyclona l and monoclonal antibodies already available for microcystin detection, ph age display technology represents a cheaper, more rapid alternative for the production of anti-microcystin antibodies than the methods currently in us e. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.