A NOVEL PROTEIN IMMUNOASSAY WITH PREDETERMINED SPECIFICITY USING MONOCLONAL-ANTIBODIES AGAINST TRYPTIC FRAGMENTS - APPLICATION TO HIV P24 ANTIGEN

We have developed a new protein immunoassay method which uses antibodi es raised against synthetic peptides. These synthetic peptides are sel ected to correspond to fragments of the protein that can be obtained b y proteolytic treatment of the protein by trypsin. Just before assay, biological samples are treated with trypsin to liberate the fragments which bind to the anti-peptide antibodies with high affinity. The exac t specificity of the assay is predetermined by the amino acid sequence of the fragment which may be either conserved within a family of anti gens Or, conversely, entirely specific for a particular protein. This method has been successfully employed in the development of an immunoa ssay for HIV P24 antigen. In that case, peptides were selected that we re strongly conserved among the different HIV-1 and HIV-2 strains. Thi s methodology has permitted the development of a sensitive immunoassay with a broad specificity despite many amino acid variations between H IV strains. The methodology could be extended to other protein antigen s.