Effector functions of differentially glycosylated anti-Bet v 1 human IgG subclasses

对桦树花粉过敏的特征在于产生针对主要过敏原Bet v 1的IgE和IgG抗体（Abs）。成功的过敏原特异性免疫疗法（SIT;脱敏），以打击桦树花粉过敏，往往与大量增加Bet v 1反应性血清IgG抗体，主要是IgG 1和IgG 4。关于这些抗Bet v 1 IgG Ab的功能的共同想法是它们捕获过敏原并抑制其与结合于肥大细胞的促炎性IgE的结合。然而，最近已经表明IgG Ab的Fc N-糖基化模式决定了它们的促炎或抗炎效应子功能：无半乳糖基化（非半乳糖基化和非唾液酸化; G 0）IgG Ab是促炎性的，而半乳糖基化加唾液酸化的IgG Ab是抗炎性的。我们已经表明在小鼠中用蛋白抗原成功诱导耐受后和在人中SIT后诱导唾液酸化IgGAb，提示唾液酸化的变应原特异性IgG抗体参与这种SIT依赖性耐受诱导。进一步的结果表明，唾液酸化，但不是G 0，抗卵清蛋白（OVA）鼠单克隆IgG 1抗体，可以减少过敏性气道炎症的OVA依赖性小鼠模型。此外，这些研究表明，含有抗原特异性唾液酸化IgG Ab的免疫复合物能够抑制树突状细胞成熟，从而引发促炎性T细胞。在这项研究中，我们希望克隆和产生差异糖基化的单克隆人源化和真实的人抗Bet v 1 IgG 1和IgG 4 Ab，以研究它们在人免疫细胞培养测定中的抑制潜力，与差异糖基化鼠抗Bet v 1 IgG 1 Ab平行，在Bet v 1依赖性小鼠过敏模型中。在该小鼠模型中，我们还希望表征差异糖基化IgG Ab的受体复合物。此外，我们希望分析皮下SIT之前、期间和之后人抗Bet v 1血清IgG Ab的Fc糖基化模式。总体而言，我们希望鉴定最佳Fc糖基化变应原特异性人IgG亚类以抑制过敏反应并表征其功能作用。这将是重要的验证成功的SIT，可能的发展抗体的被动免疫和优化个性化的SIT协议。

Allergy to birch pollen is characterized by the development of IgE and IgG antibodies (Abs) against the major allergen Bet v 1. Successful allergen-specific immunotherapy (SIT; hyposensibilization) to combat birch pollen allergy is often associated with a large increase in Bet v 1-reactive serum IgG Abs, mainly IgG1 and IgG4. The common idea about the function of these anti-Bet v 1 IgG Abs is that they capture the allergen and inhibit its binding to the pro-inflammatory IgE bound to mast cells. However, it has recently been shown that the Fc N-glycosylation pattern of IgG Abs determines their pro- or anti-inflammatory effector functions: agalactosylated (non-galactosylated and non-sialylated; G0) IgG Abs are pro-inflammatory and galactosylated plus sialylated IgG Abs are anti-inflammatory.In this context, we have shown that sialylated IgG Abs are induced after successful tolerance induction with protein antigens in mice and after SIT in humans, suggesting that sialylated allergen-specific IgG Abs are involved in this SIT-dependent tolerance induction. Further results indicated that sialylated, but not G0, anti-ovalbumin (OVA) murine monoclonal IgG1 Abs, can reduce allergic airway inflammation in an OVA-dependent mouse model. Furthermore, these studies indicated that immune complexes containing antigen-specific sialylated IgG Abs are able to inhibit dendritic cell maturation and therefore priming of pro-inflammatory T cells.In this study, we want to clone and produce differentially glycosylated monoclonal humanized and real human anti-Bet v 1 IgG1 and IgG4 Abs to investigate their inhibitory potential in human immune cell culture assays and, in parallel with differentially glycosylated murine anti-Bet v 1 IgG1 Abs, in a Bet v 1-dependent mouse allergy model. In this mouse model, we also want to characterize the receptor complexes of the differentially glycosylated IgG Abs.Additionally, we want to analyze the Fc glycosylation patterns of human anti-Bet v 1 serum IgG Abs before, during and after subcutaneous SIT.Overall, we want to identify the optimal Fc glycosylated allergen-specific human IgG subclass to inhibit allergic reactions and characterize its functional role. This will be important for the validation of successful SIT, the possible development of Abs for passive immunization and the optimization of individualized SIT protocols.