A highly sensitive and dynamic immunofluorescent cytometric bead assay for the detection of HIV-1 p24

Abstract

Nucleic acid measurements are used to follow HIV-1 viral load in clinical applications while p24 ELISA is commonly used to monitor HIV-1 replication in research settings. Current ELISA assays are expensive and offer a narrow dynamic measurement range. This report describes a simple, sensitive and inexpensive bead-based assay offering a wide dynamic measurement range. This cytometric bead assay allows the detection of p24 concentrations over 4 orders of magnitude from less than 0.4pg to up to 20,000pgml(-1) in a volume of 50microl and can be combined with other measurements.

Fig. 1

A typical p24 standard curve. The graph represents the individual points of a titration curve run in quadruplicate. The CV of the data is indicated above each data point. The coefficient of determination is calculated to fit a 4 parameter logistic regression.

Fig. 2

Inter assay variation. The figure represents the inter assay variation calculated for 4 assays run in triplicates at different concentrations. For each concentration, all the data points (12 per concentration) are plotted together with the median, the interquartile box, and the range of the data. The number above each data point represents the CV of the results at the corresponding concentration.