Fukushima Atsuki, Yamaguchi Tomoko, Ishida Waka, Fukata Kazuyo, Ueno Hiasyuki
Department of Ophthalmology, Kochi Medical School, Kohasu, Nankoku-city, Japan.
Mol Vis. 2006 Apr 7;12:310-7.
The severity of allergic conjunctivitis (AC) correlates with the degree of eosinophil infiltration into the conjunctiva, which is believed to be mediated by chemokines and adhesion molecules. The adhesion molecule very late antigen (VLA)-4 and its ligand, vascular cell adhesion molecule (VCAM)-1, are known to play important roles in eosinophil infiltration. However, the expression and function of VLA-4 in AC have not been investigated in detail. We sought to characterize VLA-4-expressing cells in the conjunctivas of mice that are developing experimental AC (EC) and to determine whether the interaction between VLA-4 and VCAM-1 is needed for the infiltration of eosinophils into the conjunctiva in AC.
EC was induced in Balb/c mice by active immunization with ragweed (RW) or adoptive transfer of RW-primed splenocytes, followed by RW challenge. Twenty-four hours after RW challenge, the conjunctivas were harvested. The conjunctivas from naive mice or mice developing EC were evaluated for VLA-4 and VCAM-1 expression by immunohistochemistry and immunofluorescent analyses. To investigate whether the interaction between VLA-4 and VCAM-1 is needed for the genesis of AC, mice developing EC were treated with anti-VLA-4 or anti-VCAM-1 antibodies two h before and after RW challenge. As a control, EC-developing mice were treated with normal rat IgG. Twenty-four hours after RW challenge, the conjunctivas were harvested for histological analysis.
Upon induction of EC, VLA-4-expressing cells infiltrated the conjunctiva but the constitutive VCAM-1 expression around conjunctival vessels was not augmented. Immunofluorescent analyses demonstrated that most of the T cells infiltrating the conjunctiva expressed VLA-4 but only half of the infiltrating eosinophils expressed it. Treatment with both anti-VLA-4 and anti-VCAM-1 antibodies significantly suppressed the infiltration of eosinophils into the conjunctiva that was induced by either active immunization or splenocyte transfer.
These results confirm that VLA-4-expressing cells infiltrate the conjunctiva and that the interaction between VLA-4 and VCAM-1 is needed for the development of EC.
过敏性结膜炎（AC）的严重程度与嗜酸性粒细胞浸润结膜的程度相关，据信这是由趋化因子和黏附分子介导的。黏附分子极迟抗原（VLA）-4及其配体血管细胞黏附分子（VCAM）-1在嗜酸性粒细胞浸润中起重要作用。然而，VLA-4在AC中的表达和功能尚未得到详细研究。我们试图对正在发生实验性过敏性结膜炎（EC）的小鼠结膜中表达VLA-4的细胞进行特征分析，并确定在AC中嗜酸性粒细胞浸润结膜是否需要VLA-4与VCAM-1之间的相互作用。
通过用豚草（RW）主动免疫或转输经RW致敏的脾细胞诱导Balb/c小鼠发生EC，随后进行RW激发。RW激发后24小时，采集结膜。通过免疫组织化学和免疫荧光分析评估未接触过抗原的小鼠或发生EC的小鼠结膜中VLA-4和VCAM-1的表达。为了研究在AC发生过程中是否需要VLA-4与VCAM-1之间的相互作用，在RW激发前后2小时用抗VLA-4或抗VCAM-1抗体处理发生EC的小鼠。作为对照，用正常大鼠IgG处理发生EC的小鼠。RW激发后24小时，采集结膜进行组织学分析。
诱导EC后，表达VLA-4的细胞浸润结膜，但结膜血管周围的组成性VCAM-1表达并未增加。免疫荧光分析表明，浸润结膜的大多数T细胞表达VLA-4，但只有一半的浸润嗜酸性粒细胞表达VLA-4。用抗VLA-4和抗VCAM-1抗体处理均显著抑制了主动免疫或脾细胞转输诱导的嗜酸性粒细胞向结膜的浸润。
这些结果证实，表达VLA-4的细胞浸润结膜，且VLA-4与VCAM-1之间的相互作用是EC发生所必需的。
