Polymorphisms of MICA recognized by human alloantibodies
Polymorphisms of MICA recognized by human alloantibodies
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DOI：
10.1007/s00251-008-0344-9
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发表时间：
2009-02-01
期刊：
影响因子：
3.2
通讯作者：
Stastny, Peter
中科院分区：
文献类型：
--
作者：
Zou, Yizhou;Qin, Zhiqiang;Stastny, Peter
云母抗原是一种表达于人内皮细胞和其他细胞表面的多态糖蛋白。在移植受者中发现了针对MICA的抗体，并发现与同种异体肾移植存活率下降有关。在目前的工作中，我们研究了抗MICA抗体识别的多态性。获得了11个常见等位基因、2个杂交等位基因和2个单一氨基酸突变等位基因的MICA重组蛋白。用与Luminex珠子结合的云母来确定反应模式。在一些研究中，含有抗MICA抗体的血清被转染MICA*001、MICA*002、MICA*008和MICA*009的细胞株或与未转染的细胞吸收，然后测试与珠子结合的MICA蛋白的抗体反应性。这项研究中使用的单抗和血清被发现识别多达14个不同的MICA表位，这一点从它们的不同吸收/反应模式中得到证明。在这些表位中，有9个表位与单一的唯一氨基酸相关：一个表位共享两个特征氨基酸，一个表位共享三个邻近的特征氨基酸，三个表位涉及非线性序列中的多个氨基酸。鉴定了两组公共表位(MICA-G1和MICA-G2)。在单一的MICA抗原小球试验中，通过与MICA转染体的吸收，通过反应性损失来确定MICA共有表位。由于这些表位可能是抗体结合的靶点，也可能是抗体介导的同种异体移植排斥反应的靶点，因此识别表位有助于了解MICA抗体的发展，并为致敏的移植受者寻找合适的供体。
MICA antigens are polymorphic glycoproteins expressed on the surface of human endothelial cells and other cells. Antibodies against MICA have been found in transplant recipients and were found to be associated with decreased survival of kidney allografts. In the present work, we investigated the polymorphisms that are recognized by antibodies against MICA. Soluble MICA recombinant proteins representing 11 common alleles, two hybrid alleles, and two single amino acid mutated alleles were produced. Patterns of reactivity were determined with MICA bound to Luminex beads. In some studies, sera containing antibodies against MICA were absorbed by cell lines transfected with MICA*001, MICA*002, MICA*008, and MICA*009 or with untransfected cells, followed by testing of antibody reactivity against MICA proteins bound to beads. The monoclonal antibodies and sera used in this study were found to recognize up to 14 distinct MICA epitopes as demonstrated by their differential absorption/reactivity patterns. Among these, nine epitopes correlated with a single unique amino acid: one shared two signature amino acids, one shared three signature amino acids in close proximity, and three epitopes involved multiple amino acids in a nonlinear sequence. Two groups of public epitopes (MICA-G1 and MICA-G2) were characterized. MICA shared epitopes were determined by reactivity loss in single MICA antigen bead assays by absorption with MICA transfectants. Since these epitopes may be targets for antibody binding and possibly antibody-mediated allograft rejection, epitope identification may help understand the development of MICA antibodies and to identify suitable donors for sensitized transplant recipients.