RESUMEN
Objective Benzothiazole derivative BD960 has immunosuppressive activity after cell -based assays for high-throughput screening.The paper aimed to investigate the involved mechanism of BD960 on T cell proliferation. Methods Human peripheral blood T-lymphocytes were isolated and purified by the immunomagnetic microbeads.Then the T cells were activated by anti-CD3/anti-CD28 mAbs or alloantigen.The effect of BD960 on activa-ted T cell proliferation, the cytotoxic effect BD960 on resting T cells and the expression of activated T cells marker CD25 were measured by flow cytometer.Cytokine levels, including IL-2, IL-4, IL-6, IL-10, IL-17A and IFN-γ, were determined by ELISA. Results BD960 significantly inhibited the proliferation of T cells stimulated by anti-CD3/anti-CD28 mAb or alloantigen in a dose-dependent manner.The IC50 value is (2.3 ±0.3)μmol/L or (2.5 ±0.3)μmol/L, respectively.Moreover, BD960 had no obvious cytotoxic effects on rest-ing T cells and peripheral blood mononuclear cells, even at a high concentration ( up to 100μmol/L) .The ratio of CD25 expression on T cell was 69.7%after stimulated by Anti-CD3/CD28 mAbs with 72 h, the concentration (0.625、2.5、10)μmol/L of BD960 also had no potent effects on the ratio, but 0.1μmol/L FK506 could inhibit CD25 expression as low as 9.4%.The G0/G1 phase of activated T cells was 58.5%after stimulated by BD960 with 96 h.BD960 could induce cell cycle arrest at the G0/G1 phase in activated T cells with the increase of concentration and RAPA in the concentration of 0.1 μmol/L was 91.5%.In addition, BD960 (0.625、2.5、10)μmol/L could inhibit the secretion of IFN-γ, IL-6 and IL-17 in activated T cells with the increase of concentration, without any effects on the secretion of IL-2, IL-4 and IL-10. Conclusion BD960 not only exerts the inhibition on the late stage of T cell activation of cell proliferation but also inhibits the secretion of inflammatory cytokines, such as IL-6, IL-17 and IFN-γ, while the mechanism of BD960 on T cell proliferation was not the same as FK506.As a result, BD960 has the potential to be the lead compound to develop a new immunosuppressant.