Enhancement of IgE-mediated histamine release from human basophils by viruses: role of interferon

Cultures. The previous experiments showed a correlation between enhancement of histamine release and the presence of interferon in the supernatant fluids. To test whether interferon-containing supernatant fluids could transfer the capacity to enhance histamine release, supernatant fluids from cultures 24 h after exposure to UV-inactivated HSV-1 or PRK control media were added to fresh leukocytes. The interferon titer in the supernatant fluids from the HSV-1treated cultures was 320 U/0.1 ml, while the interferon titer in the supernatant fluids from the PRK control cultures was less than 10 U/0.1 ml. These supernatant fluids were incubated with fresh leukocytes for 24 h and the cells were then washed and challenged with ragweed antigen E and the amount of histamine released was determined. The data in Fig. 5 a demonstrate that the supernatant fluids from the HSV-l-treated cultures markedly enhanced the release of histamine (P < 0.001).