Isolation of dengue virus with a human promonocyte cell line.

In October-November, 1988 there was an outbreak of dengue fever in the Kaoshiung area of southern Taiwan. We collected 100 serum samples from 96 patients at the onset of their fever for virus cultures and identification. A human promonocyte cell line (HL-CZ) established in our laboratory was used and proved to be susceptible for dengue virus propagation. Type 1 dengue virus in the HL-CZ cell culture was identified by immunofluorescence tests using monoclonal antibodies, and also by hemagglutination tests with goose red blood cells. The density of the virus particles, as measured by sucrose gradient ultracentrifugation, ranged from 1.186 to 1.224 g/ml. The virus yield from this cell culture is comparable with that from the C6/36 mosquito cell line. There was a significant correlation between the antibody responses tested with Western dot blots and hemagglutination inhibition techniques.