Abstract：
Little s antigen is mainly defined by a single nucleotide polymorphism at c.143C (p.Thr48) on the GYPB gene. Several variants on GYPB can alter the expression of s antigen. The aim of this study was to investigate the molecular basis of variant s antigen expression in the Chinese population.
A total of 4983 whole blood samples were collected to screen the individuals with discrepant s typing results using two different monoclonal anti-s. Then, the sequence of GYPB exon 4 was analyzed by Sanger sequencing. Flow cytometry analysis was performed to quantify s antigen expression on red blood cells (RBCs). In vitro expression study was performed to verify the effect of the GYPB variants identified on the expression of s antigen.
Four donors were identified to have discrepant s typing results. Sanger sequencing showed that three donors carried the c.173C > G variant (p.Pro58Arg) specific for sD antigen, the other one carried a novel GYPB (c.160C > T, p.Arg54Cys) variant. Flow cytometry identified a partial and weak expression of s antigen on the RBCs of the four donors. Furthermore, in vitro expression study confirmed the effect of the two variants on the s antigen expression.
The results demonstrated that in addition to p.Thr48, the two extra amino acids p.Arg54 and p.Pro58 are also important for full expression of s antigen. Since the individuals with partial s antigen are at risk for the development of alloanti-s, it is important to select at least two different monoclonal anti-s for correct s typing.
A total of 4983 whole blood samples were collected to screen the individuals with discrepant s typing results using two different monoclonal anti-s. Then, the sequence of GYPB exon 4 was analyzed by Sanger sequencing. Flow cytometry analysis was performed to quantify s antigen expression on red blood cells (RBCs). In vitro expression study was performed to verify the effect of the GYPB variants identified on the expression of s antigen.
Four donors were identified to have discrepant s typing results. Sanger sequencing showed that three donors carried the c.173C > G variant (p.Pro58Arg) specific for sD antigen, the other one carried a novel GYPB (c.160C > T, p.Arg54Cys) variant. Flow cytometry identified a partial and weak expression of s antigen on the RBCs of the four donors. Furthermore, in vitro expression study confirmed the effect of the two variants on the s antigen expression.
The results demonstrated that in addition to p.Thr48, the two extra amino acids p.Arg54 and p.Pro58 are also important for full expression of s antigen. Since the individuals with partial s antigen are at risk for the development of alloanti-s, it is important to select at least two different monoclonal anti-s for correct s typing.
摘要：
背景：Littles抗原主要由c.143C的单核苷酸多态性定义（p。对GYPB基因的Thr48)。GYPB上的几种变体可以改变s抗原的表达。本研究旨在探讨中国人群变异体抗原表达的分子基础。
方法：共收集4983份全血样本，使用两种不同的单克隆抗体对分型结果不一致的个体进行筛查。然后，通过Sanger测序分析GYPB外显子4的序列。进行流式细胞术分析以定量红细胞(RBC)上的抗原表达。进行体外表达研究以验证所鉴定的GYPB变体对s抗原表达的影响。
结果：四个供体被鉴定为具有不一致的分型结果。Sanger测序显示，三个供体携带了c.173C>G变体（p。Pro58Arg）对sD抗原具有特异性，另一个携带了一个新的GYPB(c.160℃>T，p.Arg54Cys)变体。流式细胞术鉴定了在四个供体的红细胞上s抗原的部分和弱表达。此外，体外表达研究证实了两种变体对s抗原表达的影响。
结论：结果表明，除了p.Thr48外，两个额外的氨基酸p.Arg54和p.Pro58对于s抗原的完全表达也很重要。由于具有部分s抗原的个体存在开发同种异体s的风险，重要的是选择至少两种不同的单克隆抗s正确分型。
方法：共收集4983份全血样本，使用两种不同的单克隆抗体对分型结果不一致的个体进行筛查。然后，通过Sanger测序分析GYPB外显子4的序列。进行流式细胞术分析以定量红细胞(RBC)上的抗原表达。进行体外表达研究以验证所鉴定的GYPB变体对s抗原表达的影响。
结果：四个供体被鉴定为具有不一致的分型结果。Sanger测序显示，三个供体携带了c.173C>G变体（p。Pro58Arg）对sD抗原具有特异性，另一个携带了一个新的GYPB(c.160℃>T，p.Arg54Cys)变体。流式细胞术鉴定了在四个供体的红细胞上s抗原的部分和弱表达。此外，体外表达研究证实了两种变体对s抗原表达的影响。
结论：结果表明，除了p.Thr48外，两个额外的氨基酸p.Arg54和p.Pro58对于s抗原的完全表达也很重要。由于具有部分s抗原的个体存在开发同种异体s的风险，重要的是选择至少两种不同的单克隆抗s正确分型。
