Enzyme immunoassay to detect Postia placenta in field tests: Comparison of plate ELISA with hydrophobic cloth and cotton dipstick
C A Clausen
Standard indirect enzyme-linked immunosorbent assay in polystyrene 96-well plates was compared to hydrophobic polyester cloth and cotton dipstick for detection of wood-derived antigens from the brown-rot fungus Postia placenta. The ease of handling, larger surface area, and economics of the latter two adsorbents were surveyed for application as field tests for detection of early decay. At high antibody concentrations, the cloth ELISA (C-ELISA) exibited sensitivity comparable to the plate ELISA (P-ELISA), but at lower antibody concentrations signals diminished more rapidly for the C-ELISA. The dipstick assay lacked sensitivity even at high antibody concentrations, and suffered from inability to block a high nonspecific background. Nonporous polystyrene was judged superior to C-ELISA and cotton dipstick as the immobilizing phase for detecting antigen from Postia placenta by immunoassay, although at high antibody concentrations and increased incubation periods, C-ELISA matched the sensitivity of P-ELISA.