Predominance of one T-cell antigen receptor BV haplotype in African populations
Predominance of one T-cell antigen receptor BV haplotype in African populations
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DOI：
10.1007/s002510050036
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发表时间：
2000-03-01
期刊：
影响因子：
3.2
通讯作者：
Boylston, AW
中科院分区：
文献类型：
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作者：
Craddock, TP;Zumla, AM;Boylston, AW
人类T细胞抗原受体(TCR)是显示在抗原提呈细胞表面的人类白细胞抗原/多肽复合体的反向受体。它赋予T淋巴细胞抗原特异性，因此在病原体识别和宿主反应中发挥核心作用。TCR最常用的形式是由可变的α和β链组成的杂二聚体。我们调查了146名高加索人和165名非洲人β链四个可变区基因片段(2S1、3S1、8S3和15S1)的等位基因频率。结果显示，两个群体在等位基因频率、表型、基因型和单倍型方面存在显著的意外差异。在白种人中间。有43种表型，而在被研究的非洲人中有31种。高加索人样本中有17种单倍型，但非洲人中只有10种。这种多样性的丧失在很大程度上是由于非洲样本中一种单倍型的频率很高，它代表了65%的信息染色体。这种单倍型至少有一个拷贝存在于90%的信息量大的个体中。因此，29%的非洲人是常见单倍型的纯合子。TCRBV的遗传多样性减少是意想不到的，因为非洲人通常比其他民族表现出更大的遗传多样性。例如，与高加索人相比，非洲人的人类白细胞抗原单倍型大约是后者的两倍。纯合性也是意想不到的，因为它减少了可用于识别HLA病原体衍生多肽复合体的TCR变体的数量。
The human T-cell antigen receptor (TCR) is the counter-receptor for the HLA/peptide complex displayed on the surface of antigen-presenting cells. It confers antigen specificity on T lymphocytes and therefore plays a central role in pathogen recognition and host response. The most frequently used form of the TCR is a heterodimer composed of variable alpha and beta chains. We investigated allele frequencies for four variable-region gene segments of the beta chain (2S1, 3S1, 8S3, and 15S1) in 146 Caucasians and 165 Africans. The results reveal significant unexpected differences between the two populations for allele frequencies, phenotypes, genotypes, and haplotypes. Among Caucasians. there are 43 phenotypes, whereas there are 31 among the Africans studied. There are 17 haplotypes in the Caucasian sample but only 10 in Africans. This loss of diversity is largely due to the high frequency of one haplotype in the African sample which represents 65% of the informative chromosomes. At least one copy of this haplotype is present in 90% of informative individuals. As a result, 29% of Africans are homozygous for the common haplotype. Less genetic diversity at TCRBV is unexpected, since Africans usually show greater genetic diversity than other ethnic groups. For example, there are approximately twice as many HLA haplotypes in Africans compared to Caucasians. Homozygosity is also unexpected because it reduces the number of TCR variants available to recognize HLA pathogen-derived peptide complexes.