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

(1)用抗HLA-G单克隆抗体检测了45种组织中HLA-G抗原的表达，其中包括胎盘组织。在38例不同发育阶段的胎盘组织中，HLA-G仅表达于细胞滋养层细胞柱、细胞滋养层外壳和侵袭性细胞滋养层，而在绒毛细胞滋养层和合体滋养层均有表达。这些结果进一步证实了HLA-G抗原在妊娠免疫过程中起重要作用的假设。(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没有被剪接掉，从而排除了跨膜编码区。并成功制备了抗可溶性HLA-G抗原的单克隆抗体，用于检测胎盘和脐带血中的可溶性抗原。(3)HLA-G抗原的加工及其结合肽的研究为了深入了解HLA-G的加工及其结合肽的能力，我们对TAP阴性细胞系中HLA-G的表达进行了检测，并与野生型细胞系中的表达进行了比较。TAP阴性细胞中的膜结合HLA-G表达降低至约20%，并且可溶性抗原是野生型细胞中存在的水平的5%。膜蛋白和可溶性HLA-G蛋白结合基本上相同的肽组，所述肽组衍生自多种细胞内蛋白。

(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.