Activation Mechanism Of Taurine To The B Lymphocyte

Background: Taurine(TAU)is a very special sulfur-containing amino acid.Taurine is a non-protein amino acid,which is completely different from the 20 amino acids of other synthetic proteins.Taurine has no carboxyl group,side chain and no genetic codon to match it,so taurine can not participate in protein synthesis.Although taurine can be synthesized in the body,most of the taurine needed in the body needs a dietary supply.Taurine is abundant in mammalian tissues,cells and plasma.Taurine plays an important role in the development of central nervous system(CNS)and retina,calcium regulation,membrane stabilization,reproduction and immunity.In granulocyte(leukocytes),taurine is the only rich amino acid(20-50 m M).Although taurine has been found to play an important role in enhancing mammalian immunity,the molecular mechanism of taurine has not been clarified very clear.Objective: to elucidate the activation of B lymphocytes by Taurine and its molecular mechanism.Methods: vivo experiment: Mice were randomly divided into three groups: Control group,the Dex-induced immunosuppressive model group(M)and the TAU intervention group(M+TAU).The model was established by Dex injection for 7 days and the TAU intervention group was gavaged 100 mg/kg soluble TAU for 28 days.And then all these mice of the three groups were immunized by ovalbumin(OVA)starting from the day 21 to day 35,and once every 7 days.On the 35 th day,the mice were killed,the spleen index and cell number were measured by flow cytometry,and the plasma Ig G content in mice was determined by enzyme linked immunosorbent assay(ELISA).Vitro experiment: The effect of Taurine on lymphocytes was studied from the molecular biological point of view by using the mature B cell antigen receptor(BCR)transgenic cell model(3-83 B cell)as the experimental object.Firstly,protein phosphorylation in the downstream pathway of BCR was detected by Western blot(western blot).Cell cycle and apoptosis were detected by MTT and Flow cytometry to study the effect of taurine on the cell activity of 3-83 B cells.Molecular interaction was detected by protein immunoprecipitation(IP),molecular Fluorescence spectroscopy.Finally,molecular docking technique is used to predict intermolecular binding sites.Results: Compared with the control group,the spleen index,the number of cells and the content of Ig G in the model group mice decreased significantly after stimulation of antigen ova in vivo,but the indexes recovered obviously after the administration of taurine.And flow cytometry showed that taurine significantly activated B lymphocytes.It was found that taurine could activate the cell signaling pathway downstream of BCR in 3-83 B cells and promote cell proliferation.And taurine molecule has strong interaction with BCR by molecular interaction experiment.What’s more,we found that taurine molecule could bind to the framework regions site of CDRs(complementarity-determining regions)on Fab of Ig M.Conclusion: taurine molecules can bind to B lymphocyte surface antigen receptor,thus make B lymphocyte activation therefore enhance immunity.