V region carbohydrate and antibody expression
V region carbohydrate and antibody expression
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DOI：
10.4049/jimmunol.172.9.5489
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发表时间：
2004-05-01
影响因子：
4.4
通讯作者：
Morrison, SL
中科院分区：
文献类型：
--
作者：
Gala, FA;Morrison, SL
N-连接的碳水化合物经常在IG H链的V区发现，并且可以对Ag结合亲和力具有正面或负面影响。我们已经研究了在互补决定区2（CDR 2）中含有碳水化合物的鼠抗α（1->6）葡聚糖V-H。这种碳水化合物仍然是高甘露糖，而不是被加工成复杂的形式，如对暴露的蛋白质环上的聚糖所预期的。我们已经表明，当在多种细胞类型中产生鼠-人嵌合抗体时，聚糖保持高甘露糖。此外，当L链的CDR 1、CDR 2或CDR 3中存在另一种碳水化合物时，V-H CDR 2聚糖保持高甘露糖。重要的是，我们发现当抗葡聚糖V-H CDR 2取代抗丹酰V-H的CDR 2时，使用糖基化位点，但H链被保留在内质网中，并且不运输到高尔基体。这些结果表明，不适当的V区糖基化可能会导致无效的抗体生产从表达的IG基因。在某些情况下，由V区重排或体细胞超突变产生的碳水化合物添加序列可能导致不能正确折叠和分泌的Ab。
N-Linked carbohydrates are frequently found in the V region of Ig H chains and can have a positive or negative effect on Ag binding affinity. We have studied a murine anti-alpha(1-->6) dextran V-H that contains a.carbohydrate in complementarity-determining region 2 (CDR2). This carbohydrate remains high mannose rather than being processed to a complex form, as would be expected for glycans on exposed protein loops. We have shown that the glycan remained high mannose when murine-human chimeric Abs were produced in a variety of cell types. Also, when another carbohydrate was present in CDR1, CDR2, or CDR3 of the L chain, the V-H CDR2 glycan remained high mannose. Importantly, we found that when the anti-dextran V-H CDR2 replaced CDR2 of an anti-dansyl V-H, the glycosylation site was used, but H chains were withheld in the endoplasmic reticulum and did not traffic to the Golgi apparatus. These results suggest that inappropriate V region glycosylation could contribute to ineffective Ab production from expressed Ig genes. In some cases, a carbohydrate addition sequence generated by either V region rearrangement or somatic hypermutation may result in an Ab that cannot be properly folded and secreted.