A live human B-cell activator operating in isolation of other cellular influences.

Using a reversed haemolytic plaque assay, we demonstrate that live but not inactivated Epstein-Barr (EB) virus can induce human blood lymphocytes to polyclonal Ig (IgM and IgG) secretion in vitro. Unlike pokeweed mitogen this B-cell-activating effect takes place in relative absence of T cells. EB virus thus promises to be a tool for study of B cell function isolated from other cellular influences, although its mechanism of activation appears to be different from that of previously known B cell activators.