A human melanoma cell line highly susceptible to influenza C virus.
The relative amounts of influenza C virus-specific receptors of 25 established lines of mammalian cells including four lines of human malignant melanoma origin were compared by virus binding experiments. All the human melanoma cell cultures studied possessed two to four times more receptors than were found on MDCK cells, a cell line known to be highly susceptible to influenza C virus. It may therefore be a feature common to human melanoma cells that O-acetylsialic acid, a determinant for the attachment of influenza C virus, exists in large quantities on their surface. This is not specific to melanoma cells, however, since several human cell lines derived from lung cancer, gastric cancer, and placenta specimens also exhibited high levels of virus binding. Twenty of 25 virus-binding cell cultures were further examined for their ability to support the replication of influenza C virus. In the presence of trypsin (5 to 20 micrograms/ml), the virus was found to undergo multiple cycles of replication much more efficiently in the HMV-II line of human melanoma cells than in MDCK cells. Additionally, by using HMV-II cells as a host, we succeeded in isolating two influenza C strains (C/Yamagata/1/88, C/Yamagata/2/88) from 241 throat swabs collected from patients with acute respiratory illness.