title: Escherichia coli maltose-binding protein (MBP) directly induces mouse Th1 activation through upregulating TLR2 and downregulating TLR4 expressions.
abstract: Maltose-binding protein (MBP), a component of the maltose transport system of Escherichia coli, has been commonly thought to have minimal bioactivity. Our previous studies demonstrated that MBP could significantly enhance Bacillus Calmette-Guerin (BCG)-induced T helper 1 (Th1) cell activation in mice. In the present study, we analyzed the effect of MBP on mouse T cells and found that MBP promoted the proliferation and IFN-γ production of CD4(+) T cells, suggesting that MBP directly induces Th1 activation. To explore the mechanism of Th1 activation, the expression of Toll-like receptor 2/4 (TLR2/4) on purified mouse CD4(+) T cells was detected. The results showed that MBP up-regulated TLR2 while down-regulated TLR4 expression, accompanied by a clear increase in MyD88 expression and IκB phosphorylation. Notably, the addition of anti-TLR2 antibody abrogated the MBP-induced CD4(+) T cells proliferation, IFN-γ secretion and MyD88 expression, whereas the addition of anti-TLR4 antibody exhibited a contradictive effect. Besides, the block of either TLR2 or TLR4 both reduced IκB phosphorylation. These results above suggest that TLR2-mediated MyD88-dependent pathway contributes to MBP-induced Th1 activation, while TLR4 appears to counteract this effect via MyD88-independent pathway.
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Ni
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Guomu
authors.initials: G
authors.lastname: Liu
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Xie
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: RuiPing
authors.initials: R
authors.lastname: Zhai
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Tanxiu
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China.
authors.forename: Qiongshu
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Immunology, Norman Bethune College of Medicine, Jilin University, Changchun 130021, China. Electronic address: taiguixiang@163.com.
authors.forename: Guixiang
authors.initials: G
authors.lastname: Tai
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000276:immunology*; D005786:Gene Expression Regulation; D020672:I-kappa B Proteins / Q000378:metabolism; D016130:Immunophenotyping; D008213:Lymphocyte Activation / Q000276:immunology*; D058619:Maltose-Binding Proteins / Q000276:immunology*; D051379:Mice; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D010766:Phosphorylation; D013154:Spleen / Q000166:cytology / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism*; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; D029968:Escherichia coli Proteins; D020672:I-kappa B Proteins; D058619:Maltose-Binding Proteins; D053594:Myeloid Differentiation Factor 88; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4
keywords: CD4(+) T cell; Maltose-binding protein, MBP; TLR2; TLR4; Th1