Simultaneous application of in situ DNA hybridization and immunohistochemistry on one tissue section.

Combined application of a non-radioactive in situ DNA hybridization procedure and the immunoperoxidase technique on one tissue section is described. Of six potential protocols, only one proved to be successful. First, the immunohistochemical procedure including visualization of enzyme activity is performed; the in situ DNA hybridization protocol is then applied. Using this protocol, several antigens, detected with monoclonal antibodies, and target DNAs, detected by using biotinylated human cytomegalovirus or human papilloma virus type 16 DNA probes, could be distinguished by their peroxidase activity (brown precipitate) and alkaline phosphatase activity (purple-blue precipitate) respectively. The method allows immunophenotyping of virus-infected cells as well as simultaneous visualization of two viral parameters. This technique has important implications for research and diagnostic purposes.