Cascade immunoassay by multiple binding reactions

摘要

A method for enzyme immunoassay includes contacting under binding conditions a liquid suspected of containing an analyte, an antianalyte affixed to a solid support and a tracer having an enzyme conjugated thereto. A bound fraction is separated from the liquid and incubated in a second liquid with a masked ligand. The masked ligand is converted by the enzyme on the bound fraction to give free lignad which binds to an antiligand. A signal system, such as a signal enzyme and substrate therefor, or a label-loaded vesicle and vesicle lysing agent, is added to generate a signal used to detect or measure the analyte in the liquid. The invention includes a kit of materials useful in performing the assay of the invention.