LaCorcia Gina, Swistak Mark, Lawendowski Carla, Duan Su, Weeden Tim, Nahill Sharon, Williams John M, Dzuris John L
Transplant and Immunology Research, Genzyme Corporation, Framingham, MA 01701, USA.
Transplantation. 2009 Apr 15;87(7):966-74. doi: 10.1097/TP.0b013e31819c84b8.
Polyclonal antithymocyte globulins (ATGs) are used clinically to prevent and treat acute allograft rejection and are believed to modulate the immune response primarily by depleting T cells. However, nondepleting mechanisms may also be important mediators of graft survival. In the present study, 14 lots of thymoglobulin (rabbit ATG) were analyzed and compared for nondepletive immunomodulatory activities in vitro.
Coincubation of human peripheral blood mononuclear cells with thymoglobulin induces CD4+CD25(high)Foxp3+ regulatory T cells, which were evaluated for consistent ability to suppress T-cell activation in mixed lymphocyte reactions. The consistency of CD2, CD3, CD11a, and CD45 antigen specificities in thymoglobulin was determined using flow cytometry to measure inhibition of fluorescent monoclonal antibody binding to Jurkat T cells. A transwell chemotaxis assay was established and used to evaluate ATG-mediated inhibition of stromal cell-derived factor (SDF)-1alpha-driven Jurkat T-cell migration.
Physiologic levels of thymoglobulin produced nondepletive immunomodulatory activities, which were consistent from batch to batch. All lots of thymoglobulin induced functionally immunosuppressive regulatory T cells and inhibited monoclonal antibody binding to key T-cell surface antigens. In addition, these studies provide the first demonstration that thymoglobulin effectively inhibits CXCR4/SDF-1alpha-driven T-cell chemotaxis.
This novel, systematic in vitro analysis of 14 different manufactured lots of thymoglobulin demonstrates the overall consistency of this product and provides further insights into nondepletive mechanisms by which thymoglobulin may generate durable immunoregulation and allograft survival.
多克隆抗胸腺细胞球蛋白（ATG）在临床上用于预防和治疗急性移植排斥反应，据信主要通过消耗T细胞来调节免疫反应。然而，非消耗性机制也可能是移植存活的重要介导因素。在本研究中，分析并比较了14批胸腺球蛋白（兔ATG）的体外非消耗性免疫调节活性。
人外周血单个核细胞与胸腺球蛋白共孵育可诱导CD4+CD25（高）Foxp3+调节性T细胞，在混合淋巴细胞反应中评估其抑制T细胞活化的能力是否一致。使用流式细胞术测量荧光单克隆抗体与Jurkat T细胞结合的抑制情况，以确定胸腺球蛋白中CD2、CD3、CD11a和CD45抗原特异性的一致性。建立了Transwell趋化试验，用于评估ATG介导的对基质细胞衍生因子（SDF）-1α驱动的Jurkat T细胞迁移的抑制作用。
生理水平的胸腺球蛋白产生了非消耗性免疫调节活性，批次间具有一致性。所有批次的胸腺球蛋白均诱导出功能上具有免疫抑制作用的调节性T细胞，并抑制单克隆抗体与关键T细胞表面抗原的结合。此外，这些研究首次证明胸腺球蛋白能有效抑制CXCR4/SDF-1α驱动的T细胞趋化作用。
对14个不同生产批次的胸腺球蛋白进行的这项新颖、系统的体外分析证明了该产品的总体一致性，并进一步深入了解了胸腺球蛋白可能产生持久免疫调节和移植存活的非消耗性机制。
