SBI regulated Tfh cell proportion in a dose dependent manner.
In order to validate the in vivo findings of SBI on lymphocytes, we measured the changes of T and B cell subsets within R848-induced mice splenocytes cultures subsequent to SBI treatment. Likewise, SBI treatment successfully rectified the anomalous proportions of Treg cells, Tfh cells and plasmablast of R848-induced mice in vitro , yet had no effect on the percentages of Th1 and Th2 cells (Fig. 3A). These results indicate that SBI primarily participates in the regulation of Tfh/Treg cell equilibrium. Moreover, our data showed that SBI inhibited the frequency of Tfh cells in a dose dependent manner. With the increase of SBI concentration (0- 400μM), the inhibitory ability of SBI on Tfh cells gradually increased (Fig. 3B).