The core proteins of HIV-1 are secreted into the environment during replication in the human body. The detection of the core protein p24 (molecular mass of 24 kilodaltons) serves as an indicator of early HIV-1 infection, and assays detecting it have been available since the late 1980s. However, the development of a rapid assay for the detection of HIV-1 p24 has only recently become available. Monoclonal antibodies developed in our laboratory for research and development of a rapid HIV-1 p24 assay would provide large quantities of material at a much lower price than could be obtained in the commercial market.