Abstract
Purpose: :
IL-31 is a newly discovered T-cell cytokine that, when overexpressed in mice, results in pruritus and skin dermatitis resembling human atopic dermatitis (AD). IL-31 was regarded as a factor of AD and bronchial asthma, but the role in allergic conjunctivitis (AC) is still unknown. In this study, we investigated the effects of IL-31 on AC using a Japanese cedar pollen allergen (Cry j 1).
Methods: :
BALB/c mice (8-9 wk old) were intraperitoneally immunized with Cry j 1 (10 µg/mouse) emulsified in aluminum hydroxide hydrate gel (Alum; 5mg/300 µl) on day 0. On days 7 and 14, mice were additionally immunized with Cry j 1 (10 µg/mouse) emulsified in Alum (1 mg/300 µl). Seven days after the last immunization, mice were divided in four groups and instilled with PBS (10 µl/eye), Cry j 1 (10 µg/10 µl PBS/eye), Cry j 1 (10 µg/10 µl PBS/eye) + IL-31 (7 µg/10 µl PBS/eye), and IL-31 (7 µg/10 µl PBS/eye) once a day for three days. Clinical symptoms in the conjunctiva within 15 min after the last instillation were evaluated and 24 h later, eyes were collected for histological analysis, and infiltrating cell number in the conjunctiva was analyzed.
Results: :
Instillation of Cry j 1 + IL-31 aggravated the clinical symptoms and significantly enhanced the clinical score compared with Cry j 1 instilled group. Furthermore, infiltration of eosinophils, mononuclear cells and mast cells were enhanced in conjunctiva of Cry j 1 + IL-31 instilled group. On the other hand, instillation of IL-31 elicited no significant changes compared with PBS instilled group in clinical and histological study.
Conclusions: :
The present study revealed that IL-31 instillation with Cry j 1 aggravates allergic conjunctivitis.
Keywords: conjunctivitis • cytokines/chemokines • conjunctiva