STUDY ON THE EXPRESSION AND THE FUNCTION OF HLA-G USING ANTI-HLA-G MONOCLONAL ANTIBODY

(1) HLA-G抗原在人组织中的分布研究采用HLA-G特异性单克隆抗体免疫方法检测包括胎盘在内的45种组织中HLA-G抗原的表达情况，均未与无胎盘的抗体发生反应。在胎盘（38个样本）胎儿发育的各个阶段，HLA-G仅在细胞滋养层细胞柱、细胞滋养层外壳和侵袭性细胞滋养层上表达，但在绒毛膜绒毛细胞滋养层细胞和合胞滋养层细胞上表达。这些结果进一步证实了HLA-G抗原在妊娠免疫过程中发挥重要作用的假设。(2)可溶性HLA-G抗原的研究我们发现可溶性抗原可能是由转录本的选择性剪接产生的，其中内含子4没有剪接出来，导致跨膜编码区被排除。我们还成功制备了可溶性hla - g抗原特异性单克隆抗体，用于检测胎盘和脐带血中的可溶性抗原。(3) HLA-G抗原加工及结合肽的研究为了深入了解HLA-G的加工过程及其结合肽的能力，我们检测了HLA-G在TAP阴性细胞株中的表达，并与野生型细胞株的表达进行了比较。在TAP阴性细胞中，膜结合HLA-G的表达减少到约20%，可溶性抗原是野生型细胞中存在水平的5%。膜和可溶性HLA-G蛋白结合的肽基本上是同一组肽，这些肽来源于多种细胞内蛋白。

(1) Study on the distribution of HLA-G antigen in human tissuesFourty five kinds of tissues including placenta were examined for a expression of HLA-G antigen by immunological method using monoclonal antibody specific to HLA-G,Non of them reacted with the antibody without placenta. In placent (38 samples) at all stages of fetal development, HLA-G was expressed only on cytotrophoblastic cell column, cytotrophoblastic shell and invasive cytotrophoblas but on chorionic villous cytotrophoblast and syncytiotrophoblast. These resultsfuther substantiate the assumption that the HLA-G anti-gen play an essential role in the immunological process in pregnancy.(2) Study on a soluble HLA-G antigenWe found that the soluble antigen might be produced by the alternative splicing of the transcripts, in which the intron 4 was not spliced out resulting in excluding the transmembrane encoding region. And we also succeeded in producing monoclonal antibody specific to solubleHLA-G antigen which is used to detect the soluble antigen in placenta and cord blood.(3) Study on proccessing of HLA-G antigen and the bound peptidesTo gain insight into the processing of HLA-G and its ability to bind peptide, we undertook an examination of the expression of HLA-G in the TAP negative cell line and compared it with the expression in wild type cell line. Membrane bound HLA-G expression in the TAP negative cells is reduced to about 20%, and the soluble antigen is 5% of the levels present in the wild type cells. The membrane and soluble HLA-G proteins bind essentially the same set of peptides which are derived from a variety of intracellular proteins.