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Microsphere Immunoassay (microsphere + immunoassay)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Proof of principle: An HIV p24 microsphere immunoassay with potential application to HIV clinical diagnosis,

CYTOMETRY, Issue 3 2009
Pascale Ondoa
Abstract The measurement of CD4 counts and viral loads on a single instrument such as an affordable flow cytometer could considerably reduce the cost related to the follow-up of antiretroviral therapy in resource-poor settings. The aim of this study was to assess whether the HIV-1 p24 antigen could be measured using a microsphere-based flow cytometric (FC) assay and the experimental conditions necessary for processing plasma samples. A commercial anti-p24 antibody pair from Biomaric was used to develop a p24 microsphere immunoassay (MIA) using HIV culture supernatant as the source of antigen. The ultrasensitive Perkin Elmer enzyme immunoassay (EIA) served as a reference assay. Quantification of HIV p24 using the heat-mediated immune complex disruption format described for plasma samples was feasible using the Biomaric MIA and applicable to a broad range of HIV-1 Group M subtypes. The inclusion of a tyramide amplification step was successful and increased the fluorescence signal up to 3 logs as compared with the MIA without amplification. The analytical sensitivity of this ultrasensitive Biomaric assay reached 1 pg/mL, whereas the ultrasensitive Perkin Elmer EIA was sensitive to less than 0.17 pg/mL. Our data indicate, for the first time, that the principle of p24 detection using the heat-denatured ultrasensitive format can be applied to FC. © 2008 Clinical Cytometry Society [source]

Binding of anti-HLA class I antibody to endothelial cells produce an inflammatory cytokine secretory pattern,

JOURNAL OF CLINICAL LABORATORY ANALYSIS, Issue 3 2009
Eduardo Reyes-Vargas
Abstract Current methods are inadequate for the diagnosis of early chronic allograft rejection. The goal of this study was to determine whether ligation of anti-HLA antibodies to endothelial cells is associated with a distinctive cytokine secretory pattern. Human iliac artery endothelial cells (HIAEC) cultured in vitro were incubated with w6/32, an anti-HLA class I mAb. Culture supernatants collected daily for up to 4 days were tested for secretion of 13 cytokines using a multiplexed fluorescent microsphere immunoassay. Culture of HIAEC with medium containing mAb w6/32 supported the growth of HIAEC during the 4-day study period. Levels of the pro-inflammatory cytokines IL-1,, IL-6, IL-8, and TNF-, became significantly increased in supernatants of HIAEC incubated with the mAb w6/32. We conclude that ligation of anti-HLA class I antibodies to HLA class I antigens in endothelial cells initiates an acute inflammatory process and detecting an inflammatory cytokine secretory pattern might be useful to diagnose sub-clinical chronic allograft rejection. J. Clin. Lab. Anal. 23:157,160, 2009. © 2009 Wiley-Liss, Inc. [source]

Multiplex pathogen detection based on spatially addressable microarrays of barcoded resins

BIOTECHNOLOGY JOURNAL, Issue 7 2008
David R. Blais
Abstract Suspension microsphere immunoassays are rapidly gaining recognition in antigen identification and infectious disease biodetection due to their simplicity, versatility and high-throughput multiplex screening. We demonstrate a multiplex assay based on antibody-functionalized barcoded resins (BCRs) to identify pathogen antigens in complex biological fluids. The binding event of a particular antibody on given bead (fluorescence) and the identification of the specific pathogen agent (vibrational fingerprint of the bead) can be achieved in a dispersive Raman system by exciting the sample with two different laser lines. Anthrax protective antigen, Franciscella tularensis lipopolysaccharide and CD14 antigens were accurately identified and quantified in tetraplex assays with a detection limit of 1 ng/mL. The rapid, versatile and simple analysis enabled by the BCRs demonstrates their potential for multiplex antigen detection and identification in a reconfigurable microarray format. [source]