Quantitative detection of potato viruses X and Y (PVX, PVY) with antibodies raised in chicken egg yolk (IgY) by ELISA variants.

The suitability of purified antibodies raised in chicken egg yolk (IgY) for the detection of PVX and PVY was compared with poly- and monoclonal antibodies from mammalians in two ELISA variants as coating- or 2 nd antibody. Also IgY were rendered virus-monospecific (IgY msp ) by cross adsorption with virus by a batch method and thus ELISA sensitivity was doubled. The comparison was made on the basis of the detection limit of CsCl-gradient-purified viruses first in a model system (virus in buffer) with all ELISA parameters quantified. The lowest virus quantity eliciting A 405nm 0.1 was defined as detection limit of the assay. Virus was then detected in sap of infected plants with IgY and IgY msp and the virus concentration/g leaf tissue determined. When extensively compared with IgG from mammalians, the IgY were equally suited for virus detection. Moreover, IgY can be raised and purified less laboriously and in about 40-fold larger quantity than IgG from rabbit serum.