Background

Fusion proteins incorporating the Toll-like receptor 5 ligand flagellin are currently undergoing clinical trials as vaccine candidates for many diseases.

Objective

We studied the mechanisms of immune modulation by a flagellin:allergen fusion protein containing the Toll-like receptor 5 ligand flagellin A from Listeria monocytogenes and the birch pollen allergen Bet v 1 (recombinant flagellin A [rFlaA]:Betv1).

Methods

BALB/c mice were vaccinated with rFlaA:Betv1 in an experimental Bet v 1 sensitization model. Myeloid dendritic cells (mDCs) were differentiated from mouse bone marrow, and PBMCs were isolated from subjects with birch pollen allergy. Cells were stimulated with equimolar amounts of rFlaA, rBet v 1, rFlaA plus rBet v 1, or the rFlaA:Betv1 conjugate and analyzed for cell activation, cytokine secretion, and metabolic state.

Results

rFlaA:Betv1 displayed strong immune-modulating properties both in vivo and in vitro, as characterized by secretion of both proinflammatory and anti-inflammatory cytokines from murine mDCs and PBMCs from patients with birch allergy. rFlaA:Betv1 suppressed T_H2 responses from Bet v 1–specific CD4⁺ T cells and prevented allergic sensitization in a mouse allergy model. Aggregation of rFlaA:Betv1 resulted in stronger protein uptake accompanied by an increased resistance to microsomal digestion. Remarkably, rFlaA:Betv1 induced activation of mammalian target of rapamycin, which increased the metabolic activity of the stimulated mDCs. rFlaA:Betv1-mediated IL-10 secretion, but not proinflammatory cytokine secretion, was inhibited by rapamycin in mDCs.

Conclusion

These results provide evidence that mammalian target of rapamycin is a key player involved in prevention of T_H2 responses by flagellin A conjugate vaccines.

中文翻译：

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哺乳动物雷帕霉素靶标在鞭毛蛋白A缀合物诱导IL-10树突状细胞中预防过敏性致敏中的关键作用

背景

包含Toll样受体5配体鞭毛蛋白的融合蛋白目前正作为许多疾病的候选疫苗进行临床试验。

客观的

我们研究了鞭毛蛋白：变应原融合蛋白的免疫调节机制，该蛋白包含来自单核细胞增生性李斯特菌的Toll样受体5配体鞭毛蛋白A和桦木花粉过敏原Bet v 1（重组鞭毛蛋白A [rFlaA]：Betv1）。

方法

BALB / c小鼠在实验性Bet v 1致敏模型中接种了rFlaA：Betv1。从小鼠骨髓中分化出骨髓树突状细胞（mDCs），并从桦树花粉过敏的受试者中分离出PBMC。用等摩尔量的rFlaA，rBet v 1，rFlaA加rBet v 1或rFlaA：Betv1共轭物刺激细胞，并分析细胞活化，细胞因子分泌和代谢状态。

结果

rFlaA：Betv1在体内和体外均显示出强大的免疫调节特性，其特征是桦树过敏患者的鼠mDC和PBMC分泌促炎和抗炎细胞因子。rFlaA：Betv1抑制了来自Bet v 1特异性CD4 ^+的T _H 2反应T细胞可防止小鼠过敏模型中的过敏性致敏。rFlaA：Betv1的聚集导致更强的蛋白质吸收，同时增加了对微粒体消化的抵抗力。值得注意的是，rFlaA：Betv1诱导了雷帕霉素哺乳动物靶标的活化，从而增加了受刺激的mDC的代谢活性。雷帕霉素可抑制mDC中的rFlaA：Betv1介导的IL-10分泌，但不抑制促炎细胞因子的分泌。

结论

这些结果提供了雷帕霉素的哺乳动物靶标是鞭毛蛋白A缀合物疫苗预防T _H 2反应的关键参与者的证据。