Abstract: Abstract:Objective:To investigate the TACI - Ig on MLNLs of AA rats which induced by rhBLyS.Methods: MLNLs from AA rats were activated by rhBLyS in vitro. Set five concentrations of TACI-Ig (0.01, 0.1, 1.0, 10, 100 μg/ml) and a negative control group IgG Fc (10 μg/ml). Proliferations of MLNLs were assayed by MTT. Proportion of T cell subpopulation and activity change in MLNLs were analysed by flow cytometry.The level of IL-17 were measured by ELISA. The expression of TACI were investigated by western blotting. Results: RhBLyS can lead to proliferative accentuation in MLNLs and TACI-Ig significantly inhibit the rhBLyS stimulated proliferative reactions of lymphocytes.And TACI-Ig significantly decreased the enhanced total (CD3+CD4+ T cell) and activated (CD4+CD25+ T cell), enhanced the decreased unsensitized (CD4+CD62L+ T cell) on CD4+ T cell in MLN lymphocytes of AA rats.And TACI-Ig decreased IL-17 production and TACI expression.Conclusion: TACI-Ig has inhibitory action on both proliferation and activation of MLNLs and providing molecular pharmacology evidence for illuminating immunosuppressive action．