Taurine promotes B-cell activation by interaction with the V H /V L framework regions of B-cell receptor.

Taurine (Tau) is a special sulphur-containing amino acid and has been widely used as a dietary supplement. Although Tau exists in lymphocytes in large quantities, the physiological significance of Tau to modulate human immunity is unknown. In the present study, we first found that Tau regulates the B-cell receptor (BCR)-mediated signal transduction and induces the B cells activation. The IgG production of mice after ovalbumin immunization was also increased by Tau administration. Moreover, the isothermal titration calorimetry and surface plasmon resonance analysis have shown that Tau specifically bound to the IgG2a-BCR. The Tau could bind to IgG F(ab') 2 regions via fluorescence spectroscopy analysis. In the molecular docking analysis, Tau bound to the framework regions (FRs) of variable region of the heavy chains (V H ) and in the light chains (V L ) of IgG2a-BCR. Our results suggested that Tau could improve the activation of B cells by interaction with the V H /V L FRs of BCR.