Epicutaneous sensitization with a protein antigen induces Th17 cells.
BACKGROUND
Th17 is a newly identified effector T cell lineage which plays a central role in many human inflammatory diseases and experimental animal models. Epicutaneous sensitization with a protein antigen has been proven to induce a Th2-predominant immune response and lead to development of atopic diseases in a murine protein-patch model.


OBJECTIVE
We sought to assess the generation of Th17 cells in epicutaneous sensitization with a protein antigen and its regulation by environmental elements and genetic background.


METHODS
BALB/c, C57BL/6, and DO11.10 mice were epicutaneously immunized by patch application of the following: ovalbumin alone, or co-administration of one of TLR ligands, irritant, hapten or superantigens. IL-17 and IL-22 contents in supernatants of in vitro reactivation culture of lymph nodes cells were determined by ELISA. Frequency of IL-17-secreting CD4 T cells was measured by ELISPOT.


RESULTS
Small but significant amounts of IL-17 and IL-22 could be detected in supernatants of in vitro reactivation culture of lymph nodes cells of mice receiving patch application of ovalbumin. ELISPOT assay for IL-17 also revealed low frequency of IL-17-secreting CD4 T cells in lymph nodes cells in ovalbumin group. All TLR ligands tested including agonists for TLR2, TLR3, TLR4, TLR5, TLR7 and TLR9 as well as many environmental elements including irritant, hapten and superantigen could further promote the generation of Th17 cells. In addition, C57BL/6 mice generate less Th17 cells than BALB/c mice in epicutaneous sensitization.


CONCLUSIONS
This study demonstrates Th17 generation and its regulation by environmental elements and genetic background to a protein antigen by epicutaneous route.
Wang
Li-Fang
LF
Department of Dermatology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
Chiu
Hsien-Ching
HC
Hsu
Chih-Jung
CJ
Liu
Ching-Yi
CY
Hsueh
Yu-Han
YH
Miaw
Shi-Chuen
SC
D000818:Animals; D000941:Antigens / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D005260:Female; D006969:Hypersensitivity, Immediate / Q000235:genetics / Q000276:immunology*; D020381:Interleukin-17 / Q000235:genetics / Q000276:immunology*; D007378:Interleukins / Q000276:immunology; D008024:Ligands; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010047:Ovalbumin / Q000276:immunology; D012867:Skin / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology* / Q000378:metabolism; D051193:Toll-Like Receptors / Q000276:immunology / Q000378:metabolism; D000097043:Interleukin-22
D000941:Antigens; D016207:Cytokines; D020381:Interleukin-17; D007378:Interleukins; D008024:Ligands; D010047:Ovalbumin; D051193:Toll-Like Receptors; D000097043:Interleukin-22