Comparison of two indirect enzyme-linked immunosorbent assay procedures for detecting zucchini yellow mosaic virus.

Abstract

Two indirect enzyme-linked immunosorbent assay (I-ELISA) procedures employing intermediate antibodies of Japanese quail (Coturnix coturnix japonica Temminck et Schlegel) and hen immunoglobulins were compared on their sensitivity for detecting zucchini yellow mosaic virus (ZYMV). The I-ELISA employing quail immunoglobulin on plates coated with gamma-globulin from rabbit antiserum against ZYMV was sensitive as that on non-coated plates, capable of detecting ZYMV in purified preparation at detection limitation of 10-50μg/ml and in crude extracts of infected pumpkin leaves at dilution end point of 104-105. In the assay with hen immunoglobulin, both procedures permitted to detect purified ZYMV at minimum concentration of 5-10ng/ml. However, when antigen in crude extracts of infected pumpkin leaves was assayed, the dilution end point obtained by non-precoated I-ELISA was 106-107, compared with 105-106 of precoated I-ELISA procedure. Of the procedures tested, non-precoated I-ELISA employing hen immunoglobulin showed the highest non-specific absorbance values. Despite of the relatively low sensitivity of non-precoated I-ELISA employing quail immunoglobulin, this procedure was relatively simple and useful tool for disease diagnosis of field samples. Quail appears to have potential as a source of anti-viral immunoglobulins in non-precoated and precoated I-ELISA for detecting ZYMV and perhaps for other plant viruses.