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Appl. Environ. Microbiol., 01 1997, 263-269, Vol 63, No. 1
Q Yuan, JR Clarke, HR Zhou, JE Linz, JJ Pestka and LP Hart
The heavy-chain and kappa light-chain variable region genes of an
antizearalenone hybridoma cell line (2G3-6E3-2E2) were isolated by PCR and
joined by a DNA linker encoding peptide (Gly4Ser)3 as a single- chain Fv
(scFv) DNA fragment. The scFv DNA fragment was cloned into a phagemid
(pCANTAB5E) and expressed as a fusion protein with E tag and phage M13 p3
in Escherichia coli TG1. In the presence of helper phage M13K07, the scFv
fusion protein was displayed on the surfaces of recombinant phages.
High-affinity scFv phages were enriched through affinity selection in
microtiter wells coated with zearalenone- ovalbumin conjugate. The selected
recombinant phages were used to infect E. coli HB2151 for the production of
soluble scFv antibodies. One selected clone (pQY1.5) in HB2151 secreted a
soluble scFv antibody (QY1.5) with a high zearalenone-binding affinity
(concentration required for 50% inhibition of binding, 14 ng/ml), similar
to that of parent monoclonal antibody in a competitive indirect
enzyme-linked immunosorbent assay. However, scFv QY1.5 exhibited higher
cross- reactivity with zearalenone analogs and had greater sensitivity to
methanol destabilization than the parent monoclonal antibody did.
Nucleotide sequence analyses revealed that the light-chain portion of scFv
QY1.5 had a nucleotide sequence identity of 97% to a mouse germ line gene
VK23.32 in mouse kappa light-chain variable region subgroup V, whereas the
heavy-chain nucleotide sequence was classified as mouse heavy-chain
subgroup III (D) but without any closely related members having highly
homologous complementarity-determining region sequences. The potential of
soluble scFv QY1.5 for routine screening of zearalenone and its analogs was
demonstrated with zearalenone-spiked corn extracts.
Copyright © 1997, American Society for Microbiology
Molecular cloning, expression, and characterization of a functional single-chain Fv antibody to the mycotoxin zearalenone
Department of Botany, Michigan State University, East Lansing 48824, USA.
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