A Novel Approach to the Serology of Potyviruses Involving Affinity-purified Polyclonal Antibodies Directed towards Virus-specific N Termini of Coat Proteins

Abstract

Attempts to identify and classify distinct potyviruses and their strains have frequently been hampered by the presence of variable proportions of cross-reacting antibodies in antisera. Investigations of reactivities in electroblot immunoassays of 11 polyclonal antisera raised by injection of intact particles of potyviruses produced in different laboratories with 12 distinct potyviruses showed that such cross-reacting antibodies were directed towards the homologous core protein region of potyvirus coat proteins. A simple method was developed to obtain virus-specific antibodies using affinity chromatography. It involved removal of the surface-located, virus-specific N-terminal peptide region from particles of one potyvirus using lysyl endopeptidase, coupling of the truncated coat protein to cyanogen bromide-activated Sepharose gel, and passing antisera to different potyviruses through the column. Antibodies that did not bind to the column were found to be highly specific.