A Novel Enzyme Immunoassay Commonly Applied for Ten Strains of Pyricularia oryzae

Abstract

Antiserum against a strain of the rice blast fungus Pyricularia oryzae was elicited in rabbits immunized with its cell fragments emulsified with incomplete Freund's adjuvant. The fragments were also used as solid‐phase antigens. A highly sensitive, competitive type enzyme‐linked immunosorbent assay for P. oryzae was developed by using these two preparations as the immune reagents together with the use of β‐d‐galactosidase‐labeled anti‐rabbit IgG as the tracer. Cross‐reactivity of nine different strains of P. oryzae were measured by the assay. Sensitivity and accuracy of the assay was improved by choosing the cell fragments of the least cross‐reactive strain as the solid‐phase antigen. The improved method was successfully applied for sensitive and accurate assay of all ten strains of P. oryzae with the common measuring range between 1 and 100 ng per tube. Other species of microorganisms had little reactivity in this immunoassay indicating that the assay is specific to P. oryzae group microorganisms.

A Novel Enzyme Immunoassay for Conidia of Fusarium oxysporum f.sp. cucumerinum F504

“…Although progress in the development of EIAs has been rapid (2, 6, 8, 10, 12), applications of immunoassays have been limited to water-soluble or homogeneous suspensions of antigens or antibodies (3-5, 7, 9, 11). We have been working to develop an enzyme immunoassay method for insoluble antigens, and recently we reported three ETA methods for insoluble antigens including two fungal species, Pyricularia oryzae (11) and Fusarium oxysporum (12), and a chinese crude drug Pinellia tuber (13). The technology, named the selected antibody enzyme immunoassay (SAEIA) (13), was modified and applied to the present study.…”

Application of two types of Trypanosoma cruzi amastigotes of different virulence to ELISA for Chagas' disease.

“…In this point, the higher sensitivity and specificity in the immunofluorescein assay is quite reasonable because it uses total antigens including insoluble antigens. Kitagawa et al (1987) introduced the method to apply insoluble antigens to ELISA for quantification of some bacterias. Since some works (Gam and Neva, 1977;Aranjo and Guptill, 1984;Cossio et al, 1985) revealed that the use of amastigote antigens was more sensitive than that of epimastigote antigens, we used insoluble antigens of amastigotes of different clones or strain which were cultured in different ways and compared their efficiency as solid-phase antigens.…”

“…Some reports indicated that the use of amastigotes as antigens gave better sensitivity than that of epimastigotes (Gam and Nevo, 1977;Araujo and Guptill, 1984;Cossio et al, 1985) but this advantage was limited to the use of whole bodies of fixed amastigotes, suggesting that some important antigens were insoluble in water. Kitagawa et al (1987) reported the successful use of insoluble antigens in water for enzyme immunoassay. In the present work, we attempted to use insoluble antigens from amastigotes of two clones and one strain of T. cruzi in enzyme immunoassay to detect patients of Chagas' disease.…”