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

To rule out the possibility that residual virus, rather than interferon, was responsible for the enhancement of histamine release, leukocyte cultures were stimulated with a nonviral interferon inducer. Cultures were exposed to poly I:poly C (20 ~g/ml) for 2 h, washed, reincubated for 22 h, and then exposed to ragweed antigen E. The data in Fig. 5 b show that treatment with poly I:poly C * Leukocytes were exposed to UV-inactivated viruses at an moi of 0.1 or an equivalent dilution of control media (PRK media or allantoic fluid). $ Leukocytes were challenged with nine different concentrations of ragweed antigen E; for statistical analysis the entire histamine release curves were compared by utilizing the paired t test. The data presented are the percent histamine release at the optimal ragweed antigen E concentration ( The effect of.different concentrations of leukocyte interferon on histamine release is illustrated in Fig. 6 . The data show that as the concentration of interferon was increased, the capacity of the cells to release histamine was correspondingly enhanced. Statistically significant enhancement was found with 80 U or more of interferon per milliliter (P < 0.001), but not with 8 U/ml (P > 0.01).