title: Recombinant flagellins with partial deletions of the hypervariable domain lose antigenicity but not mucosal adjuvancy.
abstract: Flagellin contains conserved N/C domains for TLR5 binding to activate innate immunity and a middle hypervariable domain harboring the major antigenic epitopes. However, conflict results existed in the previous studies as to whether the hypervariable domain was involved in the cytokine production and adjuvancy of flagellin. Here we constructed three flagellin variants (designated as FliCDelta190-278, FliCDelta220-320, and FliCDelta180-400) with deletions in the hypervariable domain. Our data demonstrated that all deletion variants lost substantial antigenicity but not mucosal adjuvancy. Surprisingly, the variant with deletion of amino acids 220-320 (FliCDelta220-320) induced higher production of IL-8, MCP-1, and TNF-alpha, and showed higher mucosal adjuvancy than full-length FliC flagellin. Our data supported the notion that the hypervariable domain was involved in the cytokine production by flagellin and more importantly demonstrated that the hypervariable domain was important for the mucosal adjuvancy of flagellin.
authors.affiliation: State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
authors.forename: Fang
authors.initials: F
authors.lastname: Liu
authors.forename: Jingyi
authors.initials: J
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Dihan
authors.initials: D
authors.lastname: Zhou
authors.forename: Yaoqing
authors.initials: Y
authors.lastname: Chen
authors.forename: Weiwei
authors.initials: W
authors.lastname: Gai
authors.forename: Wei
authors.initials: W
authors.lastname: Shi
authors.forename: Qiaoli
authors.initials: Q
authors.lastname: Li
authors.forename: Po
authors.initials: P
authors.lastname: Tien
authors.forename: Huimin
authors.initials: H
authors.lastname: Yan
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000940:Antigenic Variation / Q000235:genetics; D016207:Cytokines / Q000096:biosynthesis; D005408:Flagellin / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D018928:Immunity, Mucosal / Q000187:drug effects*; D016056:Immunodominant Epitopes / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D019779:Salmonella enterica / Q000276:immunology*; D017384:Sequence Deletion
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D016056:Immunodominant Epitopes; D011994:Recombinant Proteins; D005408:Flagellin