Exploration for interacting protein of E.coli heat-labile enterotoxin B subunit(LTB)as adjuvant / 中国药理学通报

ABSTRACT

Aim To explore the mechanism of E.coli heat-labile enterotoxin B subunit(LTB)as adjuvant by analysis of cellular proteins interacting with LTB. Methods Whole cell proteins were purified from RAW 264.7 cell after treated with LTB or NaCl 12 h, respectively.The cellular proteins were interacted with LTB and the interacting proteins were purified by pull-down assay and identified by mass spectrography.The LTB interaction proteins were conformed with Western blot and immunofluorescence assay.Results 25 LTB interaction proteins were found,and their interaction network was mapped;four proteins (Jup,Dsp,Ddx5 and Vimentin)were indicated to be related with LTB adjuvant activity;immunofluorescence assay indicated that GM130 interacted with LTB,however,Vimentin had no interaction with LTB in vivo.After treated by LTB,the expression of β-actin was upregulated obvi-ously in RAW 264.7 cell,whereras,Hspd1 did not show any change.Conclusions LTB exerts adjuvant activity through binding to GM1 of immune cells,cau-sing endocytosis and transporting to the Golgi apparatus by vesicles.Then LTB might bind to Jup and affect TCF/LEF activity,regulating the expression of Bcl 2, IL-6,and Runx3.The result is promoted T cell and B cell proliferation,differentiation and activation by se-cretion of cytokines and immunoglobulins.