title: Chimeric flagellin expressed by Salmonella typhimurium induces an ESAT-6-specific Th1-type immune response and CTL effects following intranasal immunization.
abstract: The flagellin component FliC of Salmonella typhimurium is capable of activating the innate immune system via specific interactions with TLR5 and can also act as a carrier of foreign antigen to elicit antigen-specific immune responses. Thus, we constructed an attenuated Salmonella strain SL5928(fliC/esat) expressing chimeric flagellin that contained the ESAT-6 antigen coding sequence of Mycobacterium tuberculosis inserted into the highly variable region of the Salmonella flagellin coding gene fliC(i). The chimeric flagellin functioned normally, as demonstrated using a flagella swarming assay and electron microscopy. To analyze the effects of chimeric flagellin, the cell-mediated immune response and cytotoxic T lymphocyte (CTL) effects specific for ESAT-6 antigen were tested after intranasal immunization of mice with flagellated Salmonella SL5928(fliC/esat). The results showed that SL5928(fliC/esat) intranasal immunization can strongly elicit an ESAT-6-specific T helper (Th) 1-type immune response in mucosal lymphoid tissues, such as nasopharynx-associated lymph nodes, lung and Peyer's patches, and a Th1/Th2 response was elicited in spleen and mesenteric lymph nodes. Furthermore, intranasal immunization of SL5928(fliC/esat) produced efficient CTL effects, as demonstrated using a 5- and 6-carboxyfluorescein diacetate succinimidyl ester (CFSE) assay. Thus, our study revealed that Salmonella flagellin acts as a carrier for foreign antigen and triggers strong Th1 and CTL responses during intranasal immunization. Chimeric flagellin is potentially an effective strategy for the development of novel vaccines against tuberculosis in humans and animals.
authors.affiliation: Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.forename: Liu
authors.initials: L
authors.lastname: Liu
authors.forename: Ke
authors.initials: K
authors.lastname: Wen
authors.forename: Jinlin
authors.initials: J
authors.lastname: Huang
authors.forename: Shizhong
authors.initials: S
authors.lastname: Geng
authors.forename: Junsong
authors.initials: J
authors.lastname: Shen
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Pan
authors.forename: Xinan
authors.initials: X
authors.lastname: Jiao
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D005260:Female; D005408:Flagellin / Q000235:genetics / Q000276:immunology*; D005452:Fluoresceins / Q000032:analysis; D007113:Immunity, Innate; D018928:Immunity, Mucosal; D007114:Immunization / Q000379:methods*; D008198:Lymph Nodes / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D009169:Mycobacterium tuberculosis / Q000737:chemistry / Q000235:genetics; D010581:Peyer's Patches / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology*; D012480:Salmonella Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology / Q000276:immunology; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D005452:Fluoresceins; D011993:Recombinant Fusion Proteins; D005408:Flagellin; C093616:6-carboxyfluorescein diacetate