Detection of potential microbial antigens by immuno-PCR (PCR-amplified immunoassay)

Abstract

Immuno-PCR (PCR-amplified immunoassay; I-PCR) is a novel ultrasensitive method combining the versatility of ELISA with the sensitivity of nucleic acid amplification of PCR. The enormous exponential amplification power of PCR in an I-PCR assay leads to at least a 10 2-10 4-fold increase in sensitivity compared with an analogous ELISA. I-PCR has been used to detect many biological molecules such as proto-oncogenes, toxins, cytokines, hormones, and biomarkers for autoimmune and Alzheimer's diseases, as well as microbial antigens and antibodies, and it can be adapted as a novel diagnostic tool for various infectious and non-infectious diseases. Quantitative real-time I-PCR has the potential to become the most analytically sensitive method for the detection of proteins. The sensitivity and specificity of a real-time I-PCR assay can be enhanced further with the use of magnetic beads and nanoparticles. This review is primarily focused on the detection of potential viral, bacterial and parasitic antigens by I-PCR assay, thus enabling their application for immunological research and for early diagnosis of infectious diseases.

Diagnosis of pulmonary and extrapulmonary tuberculosis based on detection of mycobacterial antigen 85B by immuno-PCR

“…However, the presence of Ag85B in M. bovis BCG and environmental mycobacteria would unlikely impact the analysis of our results, as almost all the non-TB individuals (controls) included in the study were vaccinated with BCG and exposed to the same environment. Although exquisitely sensitive, I-PCR assay is also vulnerable to sense nonspecific signals, and the sample matrix effect thus compromises over the accuracy of test, which may be improved by using the nanoparticle-based I-PCR assay that would also support for the establishment of automated 1-step I-PCR, thus further reducing the duration of assay (Mehta et al, 2014).…”

“…I-PCR assay based on streptavidin-biotin system has limitations as there are more incubation and wash steps, which lead to background signals (Mehta et al, 2014). Therefore, we used SMCC for covalent binding of reporter DNA with antibody to design I-PCR assay for the detection of Ag85B in TB patients.…”

“…I-PCR has already been used for the detection of cytokines, toxins, and potential microbial antigens and can be adopted as a novel tool for the diagnosis of infectious diseases (Mehta et al, 2014); however, limited information is available for the detection of mycobacterial antigens. We recently demonstrated the detection of M. tuberculosis-specific individual region of difference (RD) antigens such as early secretory antigenic target-6 (ESAT-6, Rv3875), mycobacterial protein from species TB (MPT-64, Rv1980c), etc.…”

“…Immuno-polymerase chain reaction (I-PCR) combines the versatility of enzyme-linked immunosorbent assay (ELISA) with the exponential amplification capacity and sensitivity of PCR, thus leading to an enormous increase in sensitivity compared to an analogous ELISA (Malou and Raoult, 2011;Mehta et al, 2014). I-PCR has already been used for the detection of cytokines, toxins, and potential microbial antigens and can be adopted as a novel tool for the diagnosis of infectious diseases (Mehta et al, 2014); however, limited information is available for the detection of mycobacterial antigens.…”

Simple and effective label-free electrochemical immunoassay for carbohydrate antigen 19-9 based on polythionine-Au composites as enhanced sensing signals for detecting different clinical samples

“…[20][21][22] Current methods can obtain accurate and reliable detection results but usually require expensive instruments and complex operating procedures. The development of a new, facile, and cost-effective technology with improved sensitivity to detect tumor markers is urgently needed to facilitate the early diagnosis and treatment of tumors.…”