title: A fusion protein of flagellin and ovalbumin suppresses the TH2 response and prevents murine intestinal allergy.
abstract: BACKGROUND
  The Toll-like receptor (TLR) 5 agonist flagellin is associated with immunomodulatory functions.
  
  
  OBJECTIVE
  We sought to investigate whether Listeria monocytogenes-derived flagellin A (flaA) can modulate ovalbumin (OVA)-specific T-cell responses and prevent OVA-induced intestinal allergy.
  
  
  METHODS
  Bone marrow-derived myeloid dendritic cells from BALB/c, C57BL/6, or TLR signaling-deficient (MyD88(-/-)) mice were stimulated with rOVA, rflaA, rflaA plus rOVA, or a recombinant fusion protein consisting of rflaA and rOVA (rflaA:OVA). The immunomodulating properties of rflaA plus rOVA and rflaA:OVA were investigated by means of DC-T-cell coculture with CD4(+) T cells from OVA-T-cell receptor transgenic or OVA/alum-immunized mice. rflaA:OVA was applied as a prophylactic and therapeutic vaccine in a murine model of intestinal allergy.
  
  
  RESULTS
  rflaA:OVA induced upregulation of TLR5 and dose-dependent IL-6 and IL-10 secretion by myeloid dendritic cells. IL-10 contributed to repressing IL-4 and IFN-γ secretion by OVA-T-cell receptor transgenic CD4(+) T cells. Moreover, rflaA:OVA suppressed CD4(+) T cells derived from T(H)2-biased mice on OVA/alum immunization. In a murine model of intestinal allergy, prophylactic vaccination with rflaA:OVA reduced T-cell activation. Protection from intestinal allergy included suppression of OVA-specific IgE while inducing OVA-specific IgG(2a). Equimolar amounts of rflaA or rOVA provided alone or as a mixture did not have comparable effects. Moreover, therapeutic vaccination was shown to reduce allergic symptoms and T-cell activation in the spleen.
  
  
  CONCLUSIONS
  The rflaA:OVA fusion protein showed strong TLR-mediated immunomodulating capacities probably attributed by the proximity of adjuvant and allergen, leading to the prevention of intestinal allergy in a murine disease model. Therefore recombinant flaA:allergen fusion proteins are promising vaccine candidates for intervention in patients with IgE-mediated allergy.
authors.affiliation: Division of Allergology, Paul-Ehrlich-Institut, Langen, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schülke
authors.forename: Manja
authors.initials: M
authors.lastname: Burggraf
authors.forename: Zoe
authors.initials: Z
authors.lastname: Waibler
authors.forename: Andrea
authors.initials: A
authors.lastname: Wangorsch
authors.forename: Sonja
authors.initials: S
authors.lastname: Wolfheimer
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kalinke
authors.forename: Stefan
authors.initials: S
authors.lastname: Vieths
authors.forename: Masako
authors.initials: M
authors.lastname: Toda
authors.forename: Stephan
authors.initials: S
authors.lastname: Scheurer
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000485:Allergens / Q000276:immunology / Q000494:pharmacology; D000818:Animals; D005408:Flagellin / Q000276:immunology* / Q000494:pharmacology; D006967:Hypersensitivity / Q000276:immunology* / Q000517:prevention & control; D007155:Immunologic Factors / Q000276:immunology*; D007422:Intestines / Q000187:drug effects / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D010047:Ovalbumin / Q000276:immunology* / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000494:pharmacology; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*; D014612:Vaccines
chemical_list: D000276:Adjuvants, Immunologic; D000485:Allergens; D007155:Immunologic Factors; D011993:Recombinant Fusion Proteins; D014612:Vaccines; D005408:Flagellin; D010047:Ovalbumin