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Cellular mechanisms of tolerance breakdown in autoantibody production

自身抗体产生中耐受破坏的细胞机制

基本信息

批准号：
11470089
负责人：
KOYASU Shigeo
金额：
$ 3.33万
依托单位：
Keio University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11470089/
关键词：
Self tolerance T cell B cell autoimmune disease pemphigus knockout mouse Rag-2 天疱瘡ノックアウトマウス rag-2ノックアウトマウス自己抗体デスモグレイン3 養子移入

项目摘要

It is believed that mechanisms leading self-tolerance are operative in both B and T cells although those for B cells are less clarified. Since production of antibodies by B cells generally requires T cell help, breakdown of self-tolerance in both B and T cell compartments is expected to take place. Alternatively, it is possible that self-reactive B cells are widely present in our body and breakdown of T cell tolerance is sufficient to trigger autoimmunity. However, experimental data supporting this notion have rarely been obtained. We have developed a new method to generate active autoimmune disease model by employing autoantigen knockout mice. In a given knockout mice self tolerance against the defective molecule is not acquired. Adoptive transfer of lymphocytes from such autoantigen knockout mice after immunization with antigens into antigen-positive mice should provide an active disease animal model for autoimmune diseases. We have applied this method to a well characterized autoimmune disease, pemphigus vulgaris (PV). It is well established in human PV that IgG antibodies against Dsg3, a cadherin type cell-to-cell adhesion molecule expressed in stratified squamous epithelia, play a pathogenic role to cause blisters in the skin and mucous membranes. Adoptive transfer of Dsg3^<-/-> splenocytes immunized with recombinant mouse Dsg3 to Rag2^<-/-> recipient mice expressing Dsg3 resulted in the stable production of anti-Dsg3 IgG and development of PV phenotypes including oral erosions with suprabasilar acantholysis. When purified T and B cells from Dsg3^<-/->, Dsg3^<+/-> or Dsg3^<+/+> mice were mixed with various combinations and transferred to Rag2^<-/-> mice, pathogenic anti-Dsg3 IgG production was observed only with a combination of Dsg3^<-/-> T and Dsg3^<-/-> B cells but not with the other combinations. These results suggest that loss of tolerance against Dsg3 in both B and T cells is important for the development of autoimmune state of PV.

据信，导致自身耐受的机制在B和T细胞中都起作用，尽管对于B细胞的机制尚不清楚。由于由B细胞产生抗体通常需要T细胞的帮助，因此预期在B和T细胞区室中发生自身耐受性的破坏。另一种可能是，自身反应性B细胞广泛存在于我们的身体中，T细胞耐受性的破坏足以引发自身免疫。然而，支持这一观点的实验数据很少得到。我们建立了一种利用自身抗原基因敲除小鼠建立自身免疫性疾病模型的新方法。在给定的基因敲除小鼠中，不能获得针对缺陷分子的自身耐受性。在用抗原免疫后，将来自这种自身抗原敲除小鼠的淋巴细胞连续转移到抗原阳性小鼠中，应该为自身免疫性疾病提供活动性疾病动物模型。我们已经将这种方法应用于一种特征良好的自身免疫性疾病，寻常天疱疮（PV）。在人类PV中已充分确定，抗Dsg 3（一种在复层鳞状上皮中表达的钙粘蛋白型细胞间粘附分子）的IgG抗体在引起皮肤和粘膜水疱中发挥致病作用。将用重组小鼠Dsg 3免疫的Dsg 3 ^<-/->脾细胞连续转移到表达Dsg 3的Rag 2 ^<-/->受体小鼠，导致抗Dsg 3 IgG的稳定产生和PV表型的发展，包括口腔糜烂伴基底上棘层松解。当将来自Dsg 3 ^<-/->、Dsg 3 ^<+/->或Dsg 3 ^<+/+>小鼠的纯化的T和B细胞与各种组合混合并转移至Rag 2 ^<-/->小鼠时，仅在Dsg 3 ^<-/-> T和Dsg 3 ^<-/-> B细胞的组合中观察到致病性抗Dsg 3 IgG产生，而在其它组合中未观察到。这些结果表明，在B和T细胞中对Dsg 3的耐受性的丧失对于PV的自身免疫状态的发展是重要的。