Serum and Plasma Immunoglobulin G Fc N‑Glycosylation Is Stable during Storage

Immunoglobulin G (IgG) glycosylation is studied in biological samples to develop clinical markers for precision medicine, for example, in autoimmune diseases and oncology. Inappropriate storage of proteins, lipids, or metabolites can lead to degradation or modification of biomolecular features, which can have a strong negative impact on accuracy and precision of clinical omics studies. Regarding the preservation of IgG glycosylation, the range of appropriate storage conditions and time frame is understudied. Therefore, we investigated the effect of storage on IgG Fc N-glycosylation in the commonly analyzed biofluids, serum and plasma. Short-term storage and accelerated storage stability were tested by incubating samples from three healthy donors under stress conditions of up to 50 °C for 2 weeks using −80 °C for 2 weeks as the reference condition. All tested IgG glycosylation featuressialylation, galactosylation, bisection, and fucosylationremained unchanged up to room temperature as well as during multiple freeze–thaw cycles and exposure to light. Only when subjected to 37 °C or 50 °C for 2 weeks, galactosylation and sialylation subtly changed. Therefore, clinical IgG glycosylation analysis does not rely as heavily on mild serum and plasma storage conditions and timely analysis as many other omics analyses.免疫球蛋白G（Immunoglobulin G, IgG）糖基化已在生物样本中被广泛研究，旨在开发精准医学相关的临床标志物，例如应用于自身免疫性疾病与肿瘤学领域。蛋白质、脂质或代谢物的不当储存会导致生物分子特征发生降解或修饰，这会对临床组学研究的准确性与精密性造成严重负面影响。针对IgG糖基化的保存，当前对适宜储存条件与时长范围的相关研究仍较为匮乏。因此，本研究针对临床常用的生物体液——血清与血浆——中IgG Fc N-糖基化的储存影响展开探究。本研究以-80℃储存2周作为参照条件，将3名健康供者的样本置于最高50℃的应激条件下孵育2周，以此测试样本的短期储存与加速储存稳定性。所有检测的IgG糖基化特征——包括唾液酸化、半乳糖基化、平分型糖基化与岩藻糖基化——在室温条件下、多次冻融循环以及光照暴露过程中均未发生变化。仅当样本在37℃或50℃条件下储存2周时，半乳糖基化与唾液酸化才发生轻微变化。因此，相较于多数其他组学分析，临床IgG糖基化分析对血清与血浆的温和储存条件以及及时检测的依赖程度相对较低。