Immunoglobulin G is the abundant antibody present in the colostrum and milk of major dairy animals. In the present study, buffalo milk IgG was characterized for its amino acid sequence and glycan diversity using reverse phase liquid chromatography coupled to ESI-Q-TOF MS in tandem mode. Amino acid sequence analysis of heavy chain constant region revealed the presence of two IgG subtypes namely IgG1 and IgG3, with IgG1 being the abundant. The complete light chain constant region sequence was also determined. N-glycan sequence analysis at a highly conserved site Asn–Ser–Thr revealed the presence of mainly biantennary complex type with core fucosylation (34%), bisecting GlcNAc (19%) and sialylation with both Neu5Ac and Neu5Gc (14%). The observed glycan diversity in buffalo milk IgG is in part comparable with bovine colostrum as well as human, bovine, goat serum counterparts.

免疫球蛋白 G 是主要奶牛初乳和牛奶中存在的丰富抗体。在本研究中，使用反相液相色谱与串联模式的 ESI-Q-TOF MS 联用，对水牛奶 IgG 的氨基酸序列和聚糖多样性进行了表征。重链恒定区的氨基酸序列分析揭示了两种IgG亚型的存在，即IgG1和IgG3，其中IgG1是丰富的。还确定了完整的轻链恒定区序列。高度保守位点Asn-Ser-Thr 的N-聚糖序列分析揭示主要存在具有核心岩藻糖基化 (34%)、平分 GlcNAc (19%) 和具有 Neu5Ac 和 Neu5Gc 的唾液酸化 (14%) 的双触角复合物类型。在水牛奶 IgG 中观察到的聚糖多样性与牛初乳以及人、牛、山羊血清对应物部分相当。