Detection of HIV-1 p24  Gag in plasma by a nanoparticle-based bio-barcode-amplification method

• Published in: Nanomedicine (London, England) Vol. 3; no. 3; pp. 293 - 303
• Main Authors: Kim, Eun-Young, Stanton, Jennifer, Korber, Bette TM, Krebs, Kendall, Bogdan, Derek, Kunstman, Kevin, Wu, Samuel, Phair, John P, Mirkin, Chad A, Wolinsky, Steven M
• Format: Journal Article
• Language: English
• Published: England Future Medicine Ltd 01.06.2008
• Subjects: AIDS (Disease); Antibodies; Antigens; bio-barcode-amplification method; Biological Assay - methods; Blood Chemical Analysis - methods; DNA; Enzyme-linked immunosorbent assay; HIV (Viruses); HIV Core Protein p24 - blood; HIV Infections - blood; HIV testing; HIV-1; Human immunodeficiency virus 1; Humans; Immunoassay - methods; Immunomagnetic Separation; major core protein of HIV-1 (p24 Gag); Methods; Nanoparticles - chemistry; Nanoparticles - ultrastructure; Nucleic Acid Amplification Techniques - methods; Protein binding; RNA; T cells; Viral antibodies
• ISSN: 1743-5889; 1748-6963; 1748-6963
• DOI: 10.2217/17435889.3.3.293

Detection of HIV-1 in patients is limited by the sensitivity and selectivity of available tests. The nanotechnology-based bio-barcode-amplification method offers an innovative approach to detect specific HIV-1 antigens from diverse HIV-1 subtypes. We evaluated the efficacy of this protein-detection method in detecting HIV-1 in men enrolled in the Chicago component of the Multicenter AIDS Cohort Study (MACS). The method relies on magnetic microparticles with antibodies that specifically bind the HIV-1 p24 Gag protein and nanoparticles that are encoded with DNA and antibodies that can sandwich the target protein captured by the microparticle-bound antibodies. The aggregate sandwich structures are magnetically separated from solution, and treated to remove the conjugated barcode DNA. The DNA barcodes (hundreds per target) were identified by a nanoparticle-based detection method that does not rely on PCR. Of 112  plasma samples from HIV-1-infected subjects, 111  were positive for HIV-1 p24  Gag protein (range: 0.11-–71.5  ng/ml of plasma) by the bio-barcode-amplification method. HIV-1 p24  Gag protein was detected in only 23 out of 112  men by the conventional ELISA. A total of 34  uninfected subjects were negative by both tests. Thus, the specificity of the bio-barcode-amplification method was 100% and the sensitivity 99%. The bio-barcode-amplification method detected HIV-1 p24  Gag protein in plasma from all study subjects with less than 200  CD4  T  cells/µµl of plasma (100%) and 19 out of 20  (95%) HIV-1-infected men who had less than 50  copies/ml of plasma of HIV-1 RNA. In a separate group of 60  diverse international isolates, representative of clades   A, B, C and D and circulating recombinant forms CRF01_AE and CRF02_AG, the bio-barcode-amplification method identified the presence of virus correctly. The bio-barcode-amplification method was superior to the conventional ELISA assay for the detection of HIV-1 p24  Gag protein in plasma with a breadth of coverage for diverse HIV-1 subtypes. Because the bio-barcode-amplification method does not require enzymatic amplification, this method could be translated into a robust point-of-care test.