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目的 分析和比较不同胎龄新生儿免疫球蛋白重链 (IgH)基因CDR3序列特征 ,探讨新生儿成熟度对CDR3序列多样性的影响。方法 从 10例胎龄 2 5～ 30周的极不成熟儿、12例胎龄 31～ 36周的不成熟儿和 11例胎龄 37～ 41周的成熟儿脐血B细胞中抽提模板DNA ,使用巢式PCR技术扩增IgH基因、然后对扩增物进行克隆和CDR3序列测定。结果 ①在极不成熟儿、不成熟儿和成熟儿 ,CDR3长度分别为 2 9.4± 7.8、32 .4± 9.2和 40 .8± 10 .7bp ,其中的N区 D基因片段 N区 (NDN)长度分别为 13.5± 5 .6、16 .1± 7.8和 2 2 .0± 8.5bp。②极不成熟儿和不成熟儿优先使用DP73和DP75 ,成熟儿优先使用VH5、DP73和DP75 ;随着胎龄的增加 ,DP73和DP75的使用率下降 ,而VH5的使用率上升。③对于D基因片段的使用 ,极不成熟儿主要是DN、DQ5 2和DXP ,不成熟儿和成熟儿主要是DXP、DLR和DN。④所有新生儿中 ,JH4的使用率最高 ,其次是JH6 ,但随着胎龄增加 ,JH4和JH6的使用率下降。⑤极不成熟儿、不成熟儿和成熟儿中 ,分别 6 3.3%、6 8.8%和 92 .0 %的克隆有开放性阅读框 ,其长度为 30 3bp ,编码 10 1个氨基酸残基。结论 新生儿的早期生长发育阶段 ,IgH基因的VH D JH 重排机制已处于活化状态 ,但其多样性有限 ;新生儿体液免疫系统的发育?
Objective To analyze and compare the CDR3 sequences of immunoglobulin heavy chain (IgH) gene of neonates with different gestational age and explore the influence of neonatal maturity on the diversity of CDR3 sequences. METHODS: Ten template DNAs were extracted from 10 immature infants with gestational age ranging from 25 to 30 weeks, 12 immature infants ranging from 31 to 36 weeks gestational age and 11 mature fetal cord blood cells from 37 to 41 weeks gestational age The nested PCR technique was used to amplify the IgH gene, and then the amplification product was cloned and the CDR3 sequence was determined. Results ① In very immature infants, immature infants and mature infants, CDR3 lengths were 2 9.4 ± 7.8, 32.4 ± 9.2 and 40.8 ± 10.7bp, respectively, in which the N region D gene fragment N (NDN) The lengths were 13.5 ± 5 .6, 16.1 ± 7.8 and 22.0 ± 8.5bp, respectively. ② Very premature children and immature children preferentially use DP73 and DP75, and mature children preferentially use VH5, DP73 and DP75; With the increase of gestational age, DP73 and DP75 are decreased while VH5 is increased. ③ For the use of D gene fragments, very immature children are mainly DN, DQ5 2 and DXP, immature children and mature children are mainly DXP, DLR and DN. ④ All newborns, JH4 the highest utilization rate, followed by JH6, but with increasing gestational age, JH4 and JH6 usage decreased. ⑤ Very immature children, immature children and mature children, respectively, 6 3.3%, 6 8.8% and 92. 0% of the clones have an open reading frame, the length of 30 3bp, encoding 10 1 amino acid residues. Conclusion The VH D JH rearrangement mechanism of IgH gene has been activated in the early stage of neonatal growth, but its diversity is limited. The development of humoral immune system in newborn