Erlich H, Stetler D, Sheng-Dong R, Saiki R
Fed Proc. 1984 Dec;43(15):3025-30.
The HLA class II genes control immune responsiveness to defined antigens; they encode cell surface heterodimers composed of alpha and beta glycopeptides. Recently, cDNA and genomic clones encoding these chains have been isolated, which allows molecular analysis of the class II genes. cDNA clones encoding the alpha chain of the HLA-DR antigen as well as that of another HLA class II antigen have been identified and characterized by nucleotide sequence analysis. These clones have been used as probes to isolate additional class II alpha cDNA clones in cDNA libraries and to identify polymorphisms in genomic DNA. Polymorphic restriction sites have been localized within the HLA-DR alpha gene and used as genetic markers in the analysis of families and of disease (insulin-dependent diabetes mellitus) and control populations. In addition, cDNA clones encoding the DR beta and DC beta chains were used as hybridization probes to identify DNA polymorphism. cDNA clones encoding the DR gamma (Ii) chain have also been identified; unlike the DR alpha and DR beta loci, the DR gamma gene is located on some chromosome other than chromosome 6. The genetic complexity of the human class II alpha and beta loci, as revealed by analysis with cDNA and genomic clones, is greater than that of the murine class II genes. The extent of that complexity will be defined by future work in this area.
HLA II类基因控制对特定抗原的免疫反应性；它们编码由α和β糖肽组成的细胞表面异二聚体。最近，编码这些链的cDNA和基因组克隆已被分离出来，这使得对II类基因进行分子分析成为可能。通过核苷酸序列分析，已经鉴定并表征了编码HLA-DR抗原α链以及另一种HLA II类抗原α链的cDNA克隆。这些克隆已被用作探针，以在cDNA文库中分离更多的II类α cDNA克隆，并鉴定基因组DNA中的多态性。多态性限制位点已定位在HLA-DRα基因内，并用作分析家族、疾病（胰岛素依赖型糖尿病）和对照人群的遗传标记。此外，编码DRβ和DCβ链的cDNA克隆被用作杂交探针来鉴定DNA多态性。编码DRγ（Ii）链的cDNA克隆也已被鉴定；与DRα和DRβ基因座不同，DRγ基因位于6号染色体以外的其他染色体上。通过cDNA和基因组克隆分析所揭示的人类II类α和β基因座的遗传复杂性，大于小鼠II类基因的遗传复杂性。这种复杂性的程度将由该领域未来的工作来确定。
