title: Protection against autoimmune diabetes by silkworm-produced GFP-tagged CTB-insulin fusion protein.
abstract: In animals, oral administration of the cholera toxin B (CTB) subunit conjugated to the autoantigen insulin enhances the specific immune-unresponsive state. This is called oral tolerance and is capable of suppressing autoimmune type 1 diabetes (T1D). However, the process by which the CTB-insulin (CTB-INS) protein works as a therapy for T1D in vivo remains unclear. Here, we successfully expressed a green fluorescent protein- (GFP-) tagged CTB-Ins (CTB-Ins-GFP) fusion protein in silkworms in a pentameric form that retained the native ability to activate the mechanism. Oral administration of the CTB-Ins-GFP protein induced special tolerance, delayed the development of diabetic symptoms, and suppressed T1D onset in nonobese diabetic (NOD) mice. Moreover, it increased the numbers of CD4⁺CD25⁺Foxp3⁺ T regulatory (Treg) cells in peripheral lymph tissues and affected the biological activity of spleen cells. This study demonstrated that the CTB-Ins-GFP protein produced in silkworms acted as an oral protein vaccine, inducing immunological tolerance involving CD4⁺CD25⁺Foxp3⁺ Treg cells in treating T1D.
authors.affiliation: Institute of Biochemistry, College of Life Sciences, Zhejiang University (Zijingang Campus), 388 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Qiaohong
authors.initials: Q
authors.lastname: Meng
authors.forename: Wenfeng
authors.initials: W
authors.lastname: Wang
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Shi
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Jin
authors.forename: Yaozhou
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000284:Administration, Oral; D019264:Adoptive Transfer / Q000379:methods; D000818:Animals; D001324:Autoantigens / Q000008:administration & dosage / Q000276:immunology; D016367:Baculoviridae; D015153:Blotting, Western; D012831:Bombyx; D002772:Cholera Toxin / Q000008:administration & dosage / Q000276:immunology*; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology* / Q000401:mortality / Q000473:pathology / Q000517:prevention & control / Q000628:therapy; D018572:Disease-Free Survival; D005260:Female; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D007108:Immune Tolerance; D007114:Immunization; D007328:Insulin / Q000008:administration & dosage / Q000276:immunology*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000096:biosynthesis / Q000276:immunology*; D013154:Spleen / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D001324:Autoantigens; D007328:Insulin; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D002772:Cholera Toxin