Immuno-PCR Assay for Sensitive Detection of Proteins in Real Time

The immuno-PCR (IPCR) assay combines the versatility and robustness of immunoassays with the exponential signal amplification power of the polymerase chain reaction (PCR). Typically, IPCR allows a 10-1,000-fold increase in sensitivity over the analogous enzyme-linked immunosorbent assay (ELISA). This is achieved by replacing the signal-producing antibody-enzyme conjugate of an ELISA with an antibody-DNA conjugate that serves as a marker for PCR amplification. The amplification power of the PCR allows for the detection of even single molecules of nucleic acid templates, making it well suited for a broad range of applications. Here, we describe the application of an IPCR assay for detection of trace amount of antigens using ricin as an example.