Four years ago, EUROIMMUN launched the Anti-PR3-Capture ELISA which has been the most competent test system for the serological diagnosis of Wegener's granulomatosis. In the meantime, a group of scientists from the Institute for Experimental Immunology (an institution of the EUROIMMUN AG) succeeded in recombinantly synthesising PR3 in production scale in a human cell line, where it undergoes authentic-posttranslational modification, in contrast to conventionally used heterologous expression systems such as insect cells or E. coli. In recombinant PR3 the proteolytically active centre is artifically deactivated by exchanging one amino acid. This results in a higher stability of the protein without reducing its antigen capacity allowing large-scale production.

On this basis, EUROIMMUN developed a new test system for the determination of antibodies against PR3: the Anti-PR3-hn-hr ELISA. The test substrate is a mixture of human native (hn) and human expressed recombinant (hr) proteinase 3, thus providing an antigen spectrum which is unsurpassable. In a study carried out in cooperation with the ANCA reference centre of the University of Maastricht (Prof. Cohen-Tervaert) the combination has proven to be ideal as antigen substrate for the determination of antibodies against PR3 - even by far surpassing the approved Capture ELISA: With respect to indirect immunofluorescence, 94% of cANCA reactive sera showed a positive reaction (conventional Anti-PR3-ELISA: 78%, Anti-PR3-Capture ELISA: 88%).

Which see: Damoiseaux et al., Ann Rheum Dis 2008