Effects of Gamma-Interferon and FK506 on Resting B Cell Proliferation of New Zealand Black/White F1 Mice

We examined the effects of gamma-interferon (γ-IFN) and the new immunosuppressant FK506 on resting B cell proliferation of New Zealand black/white F1 hybrid (B/W F1) mice, an animal model of human systemic lupus erythematosus (SLE). γ-IFN and FK506 inhibited in a dose-dependent manner both B cell proliferation and autoantibody production of resting B cells respectively. There was a synergistic interaction between γ-IFN and FK506 in their inhibition and they did not exhibit cell cytotoxicity. This in vitro synergism of γ-IFN and FK506 may have clinical application in that low doses of γ-IFN and FK506 combinations may be effective to correct polyclonal B cell activation of patients with SLE.