Mechanism of T cell activation in the airways of asthma

哮喘气道T细胞激活机制

基本信息

批准号：
07670659
负责人：
IWAMOTO Itsuo
金额：
$ 1.54万
依托单位：
Chiba University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07670659/
关键词：
Bronchial asthma T cell receptor TCR Vbeta gene Nonatopic asthma Antigen stimulation T細胞抗原レセプター遺伝子 T細胞活性化核酸塩基配列

项目摘要

Asthma is characterized by airway inflammation with prominent infiltrates of eosinophils and CD4 T cells. However, the mechanism by which T cells of nonatopic asthmatics are activated is unknown. To determine whether T cells are clonally activated by an unidentified antigen in nonatopic asthma, we analyzed T cell receptor (TCR) Vbeta genes of T cells in bronchoalveolar lavage fluids (BALF) of nonatopic asthmatics by using RT-PCR and subsequent single-strand conformation polymorphism (SSCP) analysis. PCR-SSCP analysis showed that several clonotypic bands in smears were found in most of Vbeta genes from BALF and PBL of nonatopic asthma patients. The numbers of the bands encoding each Vbeta gene from BALF significantly increased as compared with those from PBL in four of seven subjects (P<0.05). In addition, the numbers of T cell clones expressing TCR Vbeta6, Vbeta12, and Vbeta17 genes in BALF significantly increased in comparison to those in PBL (p<0.05). Moreover, sequencing analysis of CDR3 region of TCR Vbeta genes from BALF-accumulated T cell clones showed that several increased amino acid motifs were found in six subjects analyzed at a frequency of approximately 8-9% of sequenced clones, which were specifically found in each individual patient. Interestingly, two clones sharing an identical motif PF in CDR3 region with different Jbeta gene usage were detected in one patient. Moreover, one conserved amino acid sequence PTGTAG was detected in two patients who shared a common HLA-DR allele. These results suggest that infiltrating T cells in the airways of nonatopic asthmatics might recognize relatively limited epitopes of antigens in the airways and expand by the antigendriven stimulation.

哮喘的特征是气道炎症，伴有明显的嗜酸性粒细胞和 CD4 T 细胞浸润。然而，非过敏性哮喘患者的 T 细胞被激活的机制尚不清楚。为了确定非特应性哮喘中 T 细胞是否被未知抗原克隆激活，我们通过使用 RT-PCR 和随后的单链构象分析了非特应性哮喘患者支气管肺泡灌洗液 (BALF) 中 T 细胞的 T 细胞受体 (TCR) Vbeta 基因多态性（SSCP）分析。 PCR-SSCP分析显示，非特应性哮喘患者BALF和PBL的大部分Vbeta基因涂片中发现多个克隆型条带。 7 名受试者中有 4 名来自 BALF 的编码各 Vbeta 基因的条带数量与来自 PBL 的条带数量相比显着增加（P<0.05）。此外，与 PBL 中相比，BALF 中表达 TCR Vbeta6、Vbeta12 和 Vbeta17 基因的 T 细胞克隆数量显着增加（p<0.05）。此外，对 BALF 积累的 T 细胞克隆的 TCR Vbeta 基因的 CDR3 区域进行测序分析表明，在分析的 6 名受试者中发现了几个增加的氨基酸基序，频率约为测序克隆的 8-9%，这些基序在每个受试者中都特别发现。个别患者。有趣的是，在一名患者体内检测到两个在 CDR3 区域共享相同基序 PF 且 Jbeta 基因使用不同的克隆。此外，在两名具有共同 HLA-DR 等位基因的患者中检测到一个保守氨基酸序列 PTGTAG。这些结果表明，非特应性哮喘患者气道中的浸润 T 细胞可能识别气道中相对有限的抗原表位，并通过抗原驱动的刺激而扩展。