SELECTION OF AN SCFV PHAGE ANTIBODY THAT RECOGNIZES BLUETONGUE VIRUS FROM A LARGE SYNTHETIC LIBRARY AND ITS USE IN ELISAS TO DETECT VIRAL-ANTIGEN AND ANTIBODIES

A filamentous phage library displaying a vast repertoire of synthetic single chain fragment variable (scFv) antibody fragments was subjected to affinity selection on purified bluetongue virus (BTV) particles. A fter four rounds of selection and amplification, 73 out of a total of 90 fusion phage clones tested were found to bind to purified BTV in EL ISA. One of these, the clone producing the highest ELISA signal, was s elected for an investigation of its potential as an immunodiagnostic r eagent. The binding of this phage antibody (designated A12) could be i nhibited by free virus and by antibodies in immune serum. Inhibition w ith antibodies in guinea-pig sera suggested that it recognized an anti genic region on BTV that was similar on at least 10 different BTV sero types. A sandwich ELISA utilizing antibody A12 was capable of detectin g approximately 60 ng of purified BTV.