Proof of principle: an HIV p24 microsphere immunoassay with potential application to HIV clinical diagnosis.

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.