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

INFECTIOUS VIRUS. Leukocytes were incubated with infectious viruses or control media for 24 h and then challenged with anti-IgE for 45 min and the amount of histamine released into the supernatant fluids was determined. The results of a typical experiment with the cells from one individual are shown in Fig. 1 . Leukocytes that had been treated with HSV-1 showed enhanced histamine release when exposed to anti-IgE (P < 0.001). At the optimum anti-IgE concentration, the cells cultured with control media released 20% histamine whereas cells cultured with HSV-1 released 36% (Fig. 1 a) . Similarly, leukocytes incubated with Influenza A and then challenged with anti-IgE showed enhanced histamine release (P < 0.001). At optimum concentrations of anti-IgE, cells treated with control allanteic fluids released 22% histamine, whereas cells treated with Influenza A released 51% histamine ( Fig. 1 b) . Incubation of cells with Adeno-1 also resulted in a statistically significant increase in histamine release (P < 0.001), although the absolute enhancement was not as pronounced as with the other viruses ( challenged with different concentrations of anti-IgE. The data in Fig. 2 show that leukocytes incubated with either infectious or UV-inactivated virus released significantly more histamine than leukocytes exposed to control media (P < 0.001). Paired t tests revealed no significant difference between the curves generated by infectious vs. UV-inactivated virus (P > 0.1). In subsequent histamine release experiments, UV-inactivated viruses were used. To see if the increase in histamine release was due to activation of phagocytesis, leukocytes were incubated with latex beads for 24 h. Analysis of the supernatant fluids after incubation of the leukocytes with anti-IgE failed to reveal any enhancement of histamine release (data not shown).