Canine kidney cell line for isolation of respiratory viruses.

By means of a continuous canine kidney cell line (MDCK), influenza viruses were rapidly isolated from specimens collected from patients with respiratory disease. The cell line proved more sensitive than either eggs or rhesus monkey cells for currently circulating influenza A and B strains. Influenza viruses caused a distinct cytopathology within 5 days of inoculation if trypsin-ethylenediamine-tetraacetic acid was incorporated into the medium. Sufficient hemagglutinin was produced on the initial tissue culture passage to allow direct identification of isolates by hemagglutinin inhibition tests. A variety of other respiratory viruses replicated in MDCK, and over a 10-month period 211 of 600 specimens (35%) yielded viruses.