Comparison of immunoradiometric assays of Bacillus anthracis spores immobilised on multispot slides and on microtitre plates.
Indirect immunoradiometric assays (IRMA) for Bacillus anthracis spores are described in which the spores were heat fixed either on multispot microscope slides or on polyvinyl or polystyrene microtitre plates. Assays on plastic plates sometimes suffered from poor intra-experiment reproducibility. Signals were higher in assays in flat-bottomed microtitre wells than in assays in slides, but assay noise, due to non-specific absorption of antibody, was higher also, giving an overall disadvantage in signal-to-noise ratio. Elution of antibody with acid gave up to a doubling in signal-to-noise ratio. When small volumes of antibody reagents were used in assays in round-bottomed plastic wells, signal and noise characteristics were similar to those of the slide assay. While the assays on plastic wells tended to be less sensitive in terms of anti-spore antibody concentration or the number of spores detectable, the larger volume of antigen suspension that could be used in plastic wells gave them an advantage in terms of the minimum antigen concentration detectable.
D000907:Antibodies, Bacterial / Q000032:analysis*; D000942:Antigens, Bacterial / Q000032:analysis / Q000276:immunology; D001408:Bacillus anthracis / Q000276:immunology / Q000502:physiology; D005455:Fluorescent Antibody Technique; D011863:Radioimmunoassay / Q000295:instrumentation / Q000379:methods*; D013171:Spores, Bacterial / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial