Effects of topical application of a recombinant staphylococcal enterotoxin A on DNCB and dust mite extract-induced atopic dermatitis-like lesions in a murine model.
BACKGROUND
Atopic dermatitis (AD) is a chronic inflammatory skin disease with biphasic T cell-mediated abnormalities. Staphylococcal superantigens contribute to the exacerbation of inflammation in AD. The underlying immunopathological mechanisms are not fully understood.


OBJECTIVE
To determine whether epicutaneous application of recombinant staphylococcal enterotoxin A (rSEA) would exacerbate AD-like allergic inflammation induced by 2, 4-dinitrochlorobenzene (DNCB) and house dust mite extract (Dermatophagoides farinae extract, DFE) in a murine model.


METHODS
We first established an AD-like model using BALB/c mice exposed to DNCB/DFE on the ear. Next, Staphylococcus (S.) aureus or rSEA were topically applied to the mice. We evaluated the clinical and histopathological features of the animals. Serum immunoglobulin levels were also measured. In addition, real-time PCR analysis of cytokines produced by T cell subsets in the ears was conducted.


RESULTS
Mice treated with S. aureus and rSEA had more severe clinical symptoms, including increased mean dermatitis scores and ear thickness, compared to animals with only AD-like lesions. Total IgE, IgG2a and serum histamine levels were increased in all groups except the normal control group. The S. aureus- and rSEA-treated groups showed increased levels of cytokines such as IL-4, IL-13, INF-γ, IL-17, and IL-18. In particular, increased cytokine expression was more conspicuous in the rSEA-treated group than in mice exposed to S. aureus.


CONCLUSIONS
The results of this study showed that topical exposure to rSEA as well as SEA-producing S. aureus aggravate atopic skin inflammation. This may be associated with the induction of a mixed Th1/Th2 type dermatitis.
Department of Dermatology,, Biomedical Research Institute, Pusan National University Hospital, Busan, Republic of Korea, Departments of.
Byung Soo
BS
Kim
Pharmacology.
Jin Kyeong
JK
Choi
Dermatology, and.
Han Jin
HJ
Jung
Dermatology, and.
Kyung Hea
KH
Park
Dermatology, and.
Yong Hyun
YH
Jang
Dermatology, and.
Weon Ju
WJ
Lee
Dermatology, and.
Seok-Jong
SJ
Lee
Pharmacology.
Sang-Hyun
SH
Kim
Microbiology, Kyungpook National University School of Medicine, 200 Dongduk-ro, Jung-gu, Daegu, 700-721, Republic of Korea.
Hee Young
HY
Kang
Microbiology, Kyungpook National University School of Medicine, 200 Dongduk-ro, Jung-gu, Daegu, 700-721, Republic of Korea.
Jung Min
JM
Kim
Yeil Skin Clinic, Daegu, Republic of Korea.
Hyun Jung
HJ
Lim
Dermatology, and.
Do Won
DW
Kim
D000279:Administration, Cutaneous; D000818:Animals; D045424:Complex Mixtures / Q000276:immunology; D003876:Dermatitis, Atopic / Q000188:drug therapy* / Q000209:etiology; D004137:Dinitrochlorobenzene; D004195:Disease Models, Animal; D004391:Dust / Q000276:immunology; D004768:Enterotoxins / Q000008:administration & dosage*; D005260:Female; D051379:Mice; D008807:Mice, Inbred BALB C; D008925:Mites; D011994:Recombinant Proteins / Q000008:administration & dosage
D045424:Complex Mixtures; D004137:Dinitrochlorobenzene; D004391:Dust; D004768:Enterotoxins; D011994:Recombinant Proteins; C026066:enterotoxin A, Staphylococcal
Atopic dermatitis; Murine model; Staphylococcal enterotoxin A; Staphylococcus aureus