Institute of Immunology, Medical Faculty Carl Gustav Carus, Technical University Dresden, Dresden, Germany.
PLoS One. 2011 Jan 21;6(1):e16315. doi: 10.1371/journal.pone.0016315.
Previously, we identified a major myeloid-derived proinflammatory subpopulation of human blood dendritic cells which we termed slanDCs (e.g. Schäkel et al. (2006) Immunity 24, 767-777). The slan epitope is an O-linked sugar modification (6-sulfo LacNAc, slan) of P-selectin glycoprotein ligand-1 (PSGL-1). As slanDCs can induce neoantigen-specific CD4+ T cells and tumor-reactive CD8+ cytotoxic T cells, they appear as promising targets for an in vivo delivery of antigens for vaccination. However, tools for delivery of antigens to slanDCs were not available until now. Moreover, it is unknown whether or not antigens delivered via the slan epitope can be taken up, properly processed and presented by slanDCs to T cells.
METHODOLOGY/PRINCIPAL FINDINGS: Single chain fragment variables were prepared from presently available decavalent monoclonal anti-slan IgM antibodies but failed to bind to slanDCs. Therefore, a novel multivalent anti-slanDC scaffold was developed which consists of two components: (i) a single chain bispecific recombinant diabody (scBsDb) that is directed on the one hand to the slan epitope and on the other hand to a novel peptide epitope tag, and (ii) modular (antigen-containing) linker peptides that are flanked at both their termini with at least one peptide epitope tag. Delivery of a Tetanus Toxin-derived antigen to slanDCs via such a scBsDb/antigen scaffold allowed us to recall autologous Tetanus-specific memory T cells.
CONCLUSIONS/SIGNIFICANCE: In summary our data show that (i) the slan epitope can be used for delivery of antigens to this class of human-specific DCs, and (ii) antigens bound to the slan epitope can be taken up by slanDCs, processed and presented to T cells. Consequently, our novel modular scaffold system may be useful for the development of human vaccines.
此前，我们鉴定出一种人血液树突状细胞的主要髓系来源的促炎亚群，我们称之为 slanDC（例如 Schäkel 等人（2006 年）免疫 24，767-777）。s lan 表位是 P 选择素糖蛋白配体-1（PSGL-1）的 O 连接糖修饰（6-磺酸 LacNAc，s lan）。由于 slanDC 可以诱导新抗原特异性 CD4+T 细胞和肿瘤反应性 CD8+细胞毒性 T 细胞，因此它们似乎是体内递呈抗原用于疫苗接种的有前途的靶标。然而，直到现在，还没有用于将抗原递送至 slanDC 的工具。此外，尚不清楚通过 slan 表位递呈的抗原是否可以被 slanDC 摄取、适当加工和呈递给 T 细胞。
方法/主要发现：从现有的十价单克隆抗 slanIgM 抗体制备单链片段变量，但未能与 slanDC 结合。因此，开发了一种新型多价抗 slanDC 支架，它由两部分组成：（i）一种单链双特异性重组二价体（scBsDb），一方面针对 slan 表位，另一方面针对新型肽表位标签，和（ii）模块化（含抗原）接头肽，其两端均带有至少一个肽表位标签。通过这种 scBsDb/抗原支架将破伤风毒素衍生抗原递送至 slanDC，使我们能够召回自体破伤风特异性记忆 T 细胞。
结论/意义：总之，我们的数据表明：（i）s lan 表位可用于将抗原递送至此类人类特异性 DC，（ii）与 slan 表位结合的抗原可被 slanDC 摄取、加工并呈递给 T 细胞。因此，我们的新型模块化支架系统可能有助于开发人类疫苗。
