Patel S D, Cope A P, Congia M, Chen T T, Kim E, Fugger L, Wherrett D, Sonderstrup-McDevitt G
Department of Microbiology and Immunology, Stanford University School of Medicine, Fairchild Building, D 345, Stanford, CA 94305-5402, USA.
Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):8082-7. doi: 10.1073/pnas.94.15.8082.
Glutamic acid decarboxylase isoform 2 (GAD65; EC 4.1.1.15) has been identified as a key target autoantigen of insulin-dependent diabetes mellitus (IDDM). IDDM is genetically associated with the major histocompatibility complex (MHC), and particular alleles from the HLA-DQ and HLA-DR loci contribute to disease. Among DR4 subtypes, HLA-DRB10401, HLA-DRB10402, and HLA-DRB10405 alleles lend susceptibility, while HLA-DRB10403 confers protection. We have utilized HLA-DR(alpha10101,beta10401) (hereafter referred to as DR0401), human CD4, murine class II null triple transgenic mice and recombinant GAD65 to generate T cell hybridomas, and we have used overlapping sets of peptides to map the immunodominant epitopes of this autoantigen. We have identified 10 immunogenic regions for GAD65, of which 6 are recognized by multiple hybridomas. These epitopes are also generated by human antigen-presenting cells and their presentation is DR0401 restricted, as shown by the use of typed human lymphoblastoid cell lines and antibody blocking experiments. Immunodominant GAD65 epitopes defined in transgenic mice correspond to GAD65 regions previously shown to elicit T cell responses specifically in DR0401 IDDM patients, underscoring the validity of this approach. Interestingly, although the major epitopes contain DR0401 binding motifs, one of the epitopes contains a DR0405 motif.
谷氨酸脱羧酶同工型2（GAD65；EC 4.1.1.15）已被确定为胰岛素依赖型糖尿病（IDDM）的关键靶自身抗原。IDDM在基因上与主要组织相容性复合体（MHC）相关，来自HLA-DQ和HLA-DR位点的特定等位基因与疾病有关。在DR4亚型中，HLA-DRB10401、HLA-DRB10402和HLA-DRB10405等位基因增加易感性，而HLA-DRB10403则具有保护作用。我们利用HLA-DR（α10101，β10401）（以下简称DR0401）、人CD4、小鼠II类缺失三转基因小鼠和重组GAD65来产生T细胞杂交瘤，并使用重叠肽组来绘制这种自身抗原的免疫显性表位。我们已经确定了GAD65的10个免疫原性区域，其中6个被多个杂交瘤识别。这些表位也由人抗原呈递细胞产生，并且如使用分型的人淋巴母细胞系和抗体阻断实验所示，它们的呈递受DR0401限制。在转基因小鼠中确定的免疫显性GAD65表位对应于先前显示在DR0401 IDDM患者中特异性引发T细胞反应的GAD65区域，强调了这种方法的有效性。有趣的是，尽管主要表位包含DR0401结合基序，但其中一个表位包含DR0405基序。
