Detection of picogram amounts of nucleic acid by dot blot hybridization

An increasing number of human proteins isolated from cell sources are being produced for pharmaceutical use. Consequently, federal agencies have required the quantitative determination of residual nucleic acids that copurify with the potential protein products. We have conducted these assays in connection with our application for licensure of Alferon Injection. We report a sensitive dot blot hybridization assay that was used to quantitate picogram (or less) amounts of nucleic acids which copurified with human proteins isolated from recombinant (S. cerevisiae) or natural (leukocytes) sources.