A polymorphic CD40 ligand (CD154) molecule mediates CD40-dependent signalling but interferes with the ability of soluble CD40 to functionally block CD154:CD40 interactions.
A polymorphic CD40 ligand (CD154) molecule mediates CD40-dependent signalling but interferes with the ability of soluble CD40 to functionally block CD154:CD40 interactions.
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多态性 CD40 配体 (CD154) 分子介导 CD40 依赖性信号传导，但会干扰可溶性 CD40 功能性阻断 CD154:CD40 相互作用的能力。
DOI：
10.1046/j.1365-2567.2000.00943.x
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发表时间：
2000
期刊：
影响因子：
6.4
通讯作者：
Covey,LR
中科院分区：
文献类型：
--
作者：
Barnhart,B;Ford,GS;Bhushan,A;Song,C;Covey,LR
我们报告了一个年轻女性患者的活化T细胞表达的CD 40配体（CD 40 L，CD 154）的天然多态性的特征。该多态性编码该分子的细胞外CD 40结合结构域中氨基酸219的非保守性Gly→Arg取代。 对异位表达多态性蛋白（CD 154/G219 R）的293个上皮细胞进行的研究显示，与不同抗CD 154单克隆抗体（mAb）和CD 40-免疫球蛋白（CD 40-IG）的结合水平降低。然而，多克隆抗血清对多态性和野生型CD 154分子的识别是相当的，这表明多态性影响蛋白质与CD 40相互作用的能力，但不会显著改变其表面表达。为了确定CD 40交联的减少是否介导功能效应的降低，测量了三种CD 40依赖性特性。我们发现诱导表面CD 23、CD 80和Iγ转录的途径响应CD 154/G219 R信号传导而被激活。然而，突变的CD 154对CD 40亲和力的降低影响了CD 40-IG有效干扰结合并有效阻断诱导的CD 80表达的能力。相比之下，我们发现5c 8 mAb（其识别多态性分子的程度与野生型CD 154相似）有效地阻断了CD 154/G219 R和CD 40之间的相互作用（通过CD 80表达测量）。这些结果表明，在疾病和移植物排斥的治疗中，CD 154分子中天然存在的多态性可能影响CD 40介导的功能被可溶性CD 40或抗CD 154 mAb阻断的能力。
We report the characterization of a naturally occurring polymorphism in CD40 ligand (CD40L, CD154) expressed by activated T cells from a young female patient. This polymorphism encodes a nonconservative Gly → Arg substitution in amino acid 219 in the extracellular, CD40 binding domain of the molecule. Studies carried out with 293 epithelial cells ectopically expressing the polymorphic protein (CD154/G219R) revealed reduced levels of binding to different anti‐CD154 monoclonal antibodies (mAb) and CD40‐immunoglobulin (CD40‐Ig). However, recognition of the polymorphic and wild‐type CD154 molecules by a polyclonal antiserum was comparable, suggesting that the polymorphism affects the ability of the protein to interact with CD40 but does not significantly alter its surface expression. To determine if reduced cross‐linking of CD40 mediated decreased functional effects, three CD40‐dependent properties were measured. We found that pathways leading to the induction of surface CD23, CD80, and Iγ transcription were activated in response to CD154/G219R signalling. However, the decrease in affinity for CD40 by the mutated CD154 affected the ability of CD40‐Ig to efficiently interfere with the binding and effectively block induced CD80 expression. In contrast, we found that the 5c8 mAb, which recognized the polymorphic molecule to a similar extent as wild‐type CD154, effectively blocked the interaction between CD154/G219R and CD40 as measured by CD80 expression. These findings suggest that naturally occurring polymorphisms in the CD154 molecule may affect the ability of CD40‐mediated functions to be blocked by soluble CD40 or anti‐CD154 mAb in the therapeutic treatment of disease and graft rejection.