Human IgE response: virus-activated IgE secretors are interleukin-2-dependent cells

The activation of human IgE-secreting B lymphocytes was difficult until the use of low cell density limiting dilution cultures, which are more efficient and eliminate regulatory growth restraints, became possible. The transformation of IgE-producing cells by Epstein-Barr virus unexpectedly required the presence of small supplements of mature T lymphocytes early in culture. Interleukin 2 (IL2, 10 U/ml) was able to completely replace T-cell supplements when added during a brief (1-2 cell cycles) but critical period, 5-8 days after infection with the virus. The observation that IgE-committed B cells are principally able to express receptors for and respond to IL2 is of experimental utility and implies the possibility that this T-cell product could be part of the complex T-cell controls which govern IgE-committed B cells.