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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显著的嗜酸性粒细胞和CD 4 T细胞浸润。然而，非特应性哮喘患者T细胞活化的机制尚不清楚。为了确定非特应性哮喘患者T细胞是否被未知抗原克隆性激活，我们采用RT-PCR和随后的单链构象多态性（SSCP）分析方法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）V β基因。PCR-SSCP分析显示，非特应性哮喘患者支气管肺泡灌洗液和外周血淋巴细胞中的大多数Vbeta基因在涂片中发现多条克隆型条带。BALF中Vbeta基因的条带数明显高于PBL（P<0.05）。另外，BALF中表达TCR V β 6、V β 12和V β 17基因的T细胞克隆的数目与PBL中的那些相比显著增加（p<0.05）。此外，来自BALF累积的T细胞克隆的TCR V β基因的CDR 3区的测序分析显示，在以约8-9%的测序克隆的频率分析的6名受试者中发现了几个增加的氨基酸基序，其特异性地发现于每个个体患者中。有趣的是，在一名患者中检测到在CDR 3区具有相同基序PF的两个克隆，其具有不同的Jbeta基因使用。此外，一个保守的氨基酸序列PTGTAG中检测到的两名患者谁共享一个共同的HLA-DR等位基因。这些结果表明，浸润在气道的非特应性哮喘患者的T细胞可能识别相对有限的抗原表位在气道和扩增的抗原驱动的刺激。