Detection of individual virus-infected cells by filter in situ hybridization

The diagnosis of virus infection by nucleic acid hybridization represents an alternative to classical virological diagnostic methods. One special technique termed 'filter in situ hybridization' consists of fixation of intact cells to nitrocellulose filters followed by hybridization with a labelled DNA probe. We demonstrate that filter in situ hybridization can be a simple and sensitive method for the detection of virus infection in cells. In an in vitro model system using a human B-lymphoma cell line infected by the lymphotropic papovavirus (LPV), it is shown that individual virus replicating cells can be detected by this method. Infection can be diagnosed even if only one out of 20,000 cells in a culture contains replicating virus. This assay may be of value as a diagnostic tool in other viral systems.