Weitzman S, Portmore J
J Immunol. 1981 Nov;127(5):2095-101.
A mouse myeloma cell line, 45.6.3, produces an IgG2b immunoglobulin (Ig) with 2 carbohydrate attachment sites on the heavy chains. One site is in the CH2 domain and the other in the VH region. The oligosaccharides at each site have different structures. The ratio of radioactive glucosamine incorporated in the VH compared with the CH2 oligosaccharide is approximately 1 to 3. In an attempt to understand this observation further, variant cell lines derived from 45.6.3 were isolated and their Ig were characterized. A ricin-resistant line, R4R1.5, has the same 2 attachment sites as the wild type, but the ratio of radioactive glucosamine in VH compared with CH2 was 1:1 and not 1:3 as in the wild type. This alteration is most probably due to cellular factors, since the Ig protein is unchanged. The M3.11 cell line produces an Ig with a polypeptide deletion involving the CH3 domain. In this Ig, a 3rd carbohydrate attachment site can be demonstrated. The percentage of radioactivity glucosamine in the CH2 domain compared with the total Ig is about 25% instead of 75% as in the wild type. These results suggest that the extent of glycosylation of different sites on Ig can be affected by both cellular factors and structural changes in the Ig protein.
一种小鼠骨髓瘤细胞系45.6.3产生一种IgG2b免疫球蛋白（Ig），其重链上有2个碳水化合物连接位点。一个位点在CH2结构域，另一个在VH区域。每个位点的寡糖结构不同。与CH2寡糖相比，VH中掺入的放射性葡糖胺的比例约为1比3。为了进一步理解这一观察结果，分离了源自45.6.3的变异细胞系，并对其Ig进行了表征。一个抗蓖麻毒素的细胞系R4R1.5与野生型具有相同的2个连接位点，但VH中放射性葡糖胺与CH2的比例为1:1，而不是野生型中的1:3。这种改变很可能是由于细胞因子，因为Ig蛋白没有变化。M3.11细胞系产生一种Ig，其多肽缺失涉及CH3结构域。在这种Ig中，可以证明有第三个碳水化合物连接位点。与总Ig相比，CH2结构域中放射性葡糖胺的百分比约为25%，而不是野生型中的75%。这些结果表明，Ig上不同位点的糖基化程度可受细胞因子和Ig蛋白结构变化的影响。
