Effects of Inteferons on Human B-cell Differentiation in vitro

The effects of interferons (IFN) on in vitro differentiation of B-lymphocytes were studied. Peripheral lymphocytes from normal subjects were cultivated under polyclonal activator pokeweed mitogen (PWN) or Epstein-Barr virus (EBV) stimulation. The secreted Ig in the culture supernatants were measured for IgM by ELISA method. To determine the cellular level of IFN action T-cell enriched fraction (Te) or B-cell enriched fraction (Be) were preincubated with IFN prior to recombination culture. IFN had modulatory activities on Ig production; at low to moderately high doses (10–1000 U/ml of IFN-alpha or 12–120 U/ml of IFN-gamma) stimulating when IFN was added until 48 hr after the start of the culture, while after 72 hr from culture start IFN suppressed Ig production. Preincubation of Be-cells with moderately high doses of IFN (120 U/ml of IFN-gamma or 1000 U/ml of IFN-alpha) prior to PWM-stimulation suppressed Ig production. Likewise, in EBV-stimulated culture, high dose IFN suppressed Ig production. But low dose of IFN enhanced ig production in EBV-stimulated culture. Preincubation of Te-cells with IFN prior to PWM-stimulation with Be-cells enhanced the Ig production. The T-cell subset analysis at the end of these culture showed enhanced ratio of T-helper cell relative to T-suppressor cells, suggesting increased T-helper cell proliferation after incubation with IFN. Thus, it is concluded that IFNs have modulatory activities on B-cell differentiation. The mechanism seems to be direct effects on B-cells (in PWM and EBV system) as well as through T-helper cell mediation (PWM system). The IFN-gamma showed more potent (2-to 6-fold) stimulatory activities than IFN-alpha.