Department of Plasma Proteins, Sanquin-AMC Landsteiner and Van Creveld Laboratory, Amsterdam, The Netherlands.
PLoS One. 2013 Nov 14;8(11):e80239. doi: 10.1371/journal.pone.0080239. eCollection 2013.
The formation of inhibitory antibodies directed against coagulation factor VIII (FVIII) is a severe complication in the treatment of hemophilia A patients. The induction of anti-FVIII antibodies is a CD4(+) T cell-dependent process. Activation of FVIII-specific CD4(+) T cells is dependent on the presentation of FVIII-derived peptides on MHC class II by antigen-presenting cells. Previously, we have shown that FVIII-pulsed human monocyte-derived dendritic cells can present peptides from several FVIII domains. In this study we show that FVIII peptides are presented on immature as well as mature dendritic cells. In immature dendritic cells half of the FVIII-loaded MHC class II molecules are retained within the cell, whereas in LPS-matured dendritic cells the majority of MHC class II/peptide complexes is present on the plasma membrane. Time-course studies revealed that presentation of FVIII-derived peptides was optimal between 12 and 24 hours after maturation but persisted for at least 96 hours. We also show that macrophages are able to internalize FVIII as efficiently as dendritic cells, however FVIII was presented on MHC class II with a lower efficiency and with different epitopes compared to dendritic cells. In total, 48 FVIII core-peptides were identified using a DCs derived of 8 different donors. Five HLA-promiscuous FVIII peptide regions were found - these were presented by at least 4 out of 8 donors. The remaining 42 peptide core regions in FVIII were presented by DCs derived from a single (30 peptides) or two to three donors (12 peptides). Overall, our findings show that a broad repertoire of FVIII peptides can be presented on HLA-DR.
抑制性抗体针对凝血因子 VIII（FVIII）的形成是治疗 A 型血友病患者的严重并发症。抗 FVIII 抗体的诱导是一个 CD4(+) T 细胞依赖性过程。FVIII 特异性 CD4(+) T 细胞的激活依赖于抗原呈递细胞上 MHC Ⅱ类呈递 FVIII 衍生肽。先前，我们已经表明 FVIII 脉冲的人单核细胞衍生的树突状细胞可以呈递来自 FVIII 几个结构域的肽。在这项研究中，我们表明 FVIII 肽在未成熟和成熟的树突状细胞上呈递。在未成熟的树突状细胞中，一半的 FVIII 加载 MHC Ⅱ类分子保留在细胞内，而在 LPS 成熟的树突状细胞中，大多数 MHC Ⅱ类/肽复合物存在于质膜上。时程研究表明，FVIII 衍生肽的呈递在成熟后 12 至 24 小时之间最佳，但至少持续 96 小时。我们还表明，巨噬细胞能够像树突状细胞一样有效地内化 FVIII，然而与树突状细胞相比，FVIII 在 MHC Ⅱ类上的呈递效率较低，并且具有不同的表位。总共使用 8 个不同供体的树突细胞鉴定了 48 个 FVIII 核心肽。发现了 5 个 HLA 混杂的 FVIII 肽区域-这些区域至少由 8 个供体中的 4 个呈递。FVIII 中剩余的 42 个肽核心区域由来自单个（30 个肽）或两个至三个供体（12 个肽）的树突细胞呈递。总的来说，我们的研究结果表明，广泛的 FVIII 肽谱可以在 HLA-DR 上呈递。
