Production of polyclonal antiserum using recombinant coat protein of Rupestris stem pitting-associated virus

RSPaV is the causal agent of pitting in the grapevine woody cylinder. The aim of this research was to produce polyclonal antiserum against recombinant RSPaV coat protein (CP) and evaluate its specificity and sensibility. The CP gene (780bp) of RSPaV was previously characterized. This gene was subcloned into the EcoRI site of the pRSET-B expression vector and the recombinant plasmid was used to induce the expression of the CP in E. coli cells. The CP, fused to a 6-His-tag, was purified from E. coli total protein extract by affinity chromatography using Ni-NTA resin. Identity of the purified protein was confirmed by SDS-PAGE and Western blot, using antibodies against the histidine tail. The in vitro-expressed recombinant CP presented a MW of ca. 31kDa. The purified protein was quantified and 2.55mg used for the immunization of a rabbit. The obtained polyclonal antiserum reacted with different RSPaV isolates extracted from grapevines in indirect ELISA.