Sorvillo Nicoletta, Hartholt Robin B, Bloem Esther, Sedek Magdalena, ten Brinke Anja, van der Zwaan Carmen, van Alphen Floris P, Meijer Alexander B, Voorberg Jan
Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands Current address: Harvard Medical School Program in Cellular and Molecular Medicine, Boston Children's Hospital, USA.
Department of Plasma Proteins, Sanquin-AMC Landsteiner Laboratory, Amsterdam, the Netherlands.
Haematologica. 2016 Mar;101(3):309-18. doi: 10.3324/haematol.2015.137067. Epub 2015 Dec 3.
It has been proposed that von Willebrand factor might affect factor VIII immunogenicity by reducing factor VIII uptake by antigen presenting cells. Here we investigate the interaction of recombinant von Willebrand factor with immature monocyte-derived dendritic cells using flow cytometry and confocal microscopy. Surprisingly, von Willebrand factor was not internalized by immature dendritic cells, but remained bound to the cell surface. As von Willebrand factor reduces the uptake of factor VIII, we investigated the repertoire of factor VIII presented peptides when in complex with von Willebrand factor. Interestingly, factor VIII-derived peptides were still abundantly presented on major histocompatibility complex class II molecules, even though a reduction of factor VIII uptake by immature dendritic cells was observed. Inspection of peptide profiles from 5 different donors showed that different core factor VIII peptide sequences were presented upon incubation with factor VIII/von Willebrand factor complex when compared to factor VIII alone. No von Willebrand factor peptides were detected when immature dendritic cells were pulsed with different concentrations of von Willebrand factor, confirming lack of von Willebrand factor endocytosis. Several von Willebrand factor derived peptides were recovered when cells were pulsed with von Willebrand factor/factor VIII complex, suggesting that factor VIII promotes endocytosis of small amounts of von Willebrand factor by immature dendritic cells. Taken together, our results establish that von Willebrand factor is poorly internalized by immature dendritic cells. We also show that von Willebrand factor modulates the internalization and presentation of factor VIII-derived peptides on major histocompatibility complex class II.
有人提出，血管性血友病因子可能通过减少抗原呈递细胞对凝血因子 VIII 的摄取来影响其免疫原性。在此，我们使用流式细胞术和共聚焦显微镜研究重组血管性血友病因子与未成熟单核细胞衍生的树突状细胞之间的相互作用。令人惊讶的是，血管性血友病因子未被未成熟树突状细胞内化，而是仍与细胞表面结合。由于血管性血友病因子会减少凝血因子 VIII 的摄取，我们研究了凝血因子 VIII 与血管性血友病因子复合时所呈递肽段的情况。有趣的是，尽管观察到未成熟树突状细胞对凝血因子 VIII 的摄取减少，但凝血因子 VIII 衍生的肽段仍大量呈递于主要组织相容性复合体 II 类分子上。对来自 5 个不同供体的肽谱检查表明，与单独的凝血因子 VIII 相比，与凝血因子 VIII/血管性血友病因子复合物孵育时会呈现不同的凝血因子 VIII 核心肽序列。当用不同浓度的血管性血友病因子刺激未成熟树突状细胞时，未检测到血管性血友病因子肽段，证实缺乏血管性血友病因子的内吞作用。当用血管性血友病因子/凝血因子 VIII 复合物刺激细胞时，回收了几种血管性血友病因子衍生的肽段，这表明凝血因子 VIII 通过未成熟树突状细胞促进少量血管性血友病因子的内吞作用。综上所述，我们的结果表明未成熟树突状细胞对血管性血友病因子的内化能力较差。我们还表明，血管性血友病因子可调节凝血因子 VIII 衍生肽段在主要组织相容性复合体 II 类分子上的内化和呈递。
