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

桦树花粉过敏的特点是产生针对主要过敏原betv1的IgE和IgG抗体（Abs）。成功的过敏原特异性免疫治疗（SIT；降敏）对抗桦树花粉过敏通常与Bet v 1反应性血清IgG抗体（主要是IgG1和IgG4）的大量增加有关。一般认为这些抗bet v 1 IgG抗体的功能是捕获过敏原并抑制其与肥大细胞上的促炎IgE的结合。然而，最近有研究表明，IgG抗体的Fc n-糖基化模式决定了其促炎或抗炎作用：无半乳糖化（非半乳糖化和非唾液化；G0） IgG抗体是促炎的，半乳糖化加唾液化的IgG抗体是抗炎的。在这种情况下，我们已经表明，唾液化的IgG抗体在小鼠和人体内的蛋白抗原成功诱导耐受性后被诱导，这表明唾液化的过敏原特异性IgG抗体参与了这种依赖于SIT的耐受性诱导。进一步的研究结果表明，唾液化而非G0的抗卵清蛋白（OVA）小鼠单克隆IgG1抗体可以减轻OVA依赖小鼠模型中的变应性气道炎症。此外，这些研究表明，含有抗原特异性唾液化IgG抗体的免疫复合物能够抑制树突状细胞的成熟，从而抑制促炎T细胞的启动。在这项研究中，我们想要克隆和生产差异糖基化的人源化和真人抗Bet v1 IgG1和IgG4单克隆抗体，以研究它们在人免疫细胞培养试验中的抑制潜力，并与差异糖基化的小鼠抗Bet v1 IgG1抗体并行，在Bet v1依赖的小鼠过敏模型中。在该小鼠模型中，我们还想表征差异糖基化IgG抗体的受体复合物。此外，我们想分析人抗betv1血清IgG抗体在皮下SIT之前、期间和之后的Fc糖基化模式。总之，我们希望确定最佳的Fc糖基化过敏原特异性人IgG亚类来抑制过敏反应并表征其功能作用。这对于成功的SIT验证、可能开发用于被动免疫的抗体和优化个体化SIT方案将是重要的。

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.