Immunological Function of HLA-G Exepressed on trophoblasts.

To understand the基本关系HLA class I To maternal-placental immune tolerance，we attempted to dissect the expression of soluble (S) HLA-G from menbrance bound (M) HLA-Gto investigate the expression of其他非经典class I，specifically HLA-E.Towards this goal，我们已经开发了一套HLA-G specific monoclonal antibodies which allow the distinction of thesoluble and membrane G1 proteinshave used these and specific anti-HLA-E reagents in immunohisto-chemical staining to localize这三个蛋白质在placental tissue. Further，我们使用HLA-G specific antibodies to isolate S·HLA-G and M·HLA-G directly from placental tissue in1. examine bound peptides. Expression of HLA-G and HLA-EImmunohistochemical staining ofplacenta demonstrated that S HLA-G was found expressed in syncyciotrophoblasts, cytotrophoblastsextravillous cytotrophoblasts and was also apparent in maternal blood at intervillous space。Consistent with previous reportsHLA-G was found expressed only in extravillous cytotrophoblasts. HLA-E was expressed weakly insynciciotrophoblasts and cytotrophoblasts and comparatively more strongly in extravillouscytotrophoblasts,essentially in parallel with total HLA-G.2. Antigen presenting ability of HLA-GTo investigate theability， TAP dependency of HLA-G表达式，and sequence of HLA-G bound peptide were examined. When HLA-G was isolated from transfected cellsa relatively large number of bound peptides derived from intra cellular proteins were标识，but the number of bound peptides was considerably smaller and the individual abundance considerablyhigher,a single peptide species accounting for 15% of the total peptide bound to HLA-G from theplacenta。

To understand the basic relationship of HLA class I to maternal-placental immune tolerance, we have attempted to dissect the expression of soluble (S) HLA-G from menbrance bound (M) HLA-G and to investigate the expression of other nonclassical class I,specifically HLA-E.Towards this goal, we have developed a set of HLA-G specific monoclonal antibodies which allow the distinction of the soluble and membrane G1 proteins, and have used these and specific anti-HLA-E reagents in immunohisto-chemical staining to localize these three proteins in placental tissue. Further, we used HLA-G specific antibodies to isolate S・HLA-G and M・HLA-G directly from placental tissue in order to examine bound peptides.1. Expression of HLA-G and HLA-EImmunohistochemical staining of placenta demonstrated that S・HLA-G was found expressed in syncyciotrophoblasts, cytotrophoblasts, and extravillous cytotrophoblasts and was also apparent in maternal blood at intervillous space. Consistent with previous reports, M・HLA-G was found expressed only in extravillous cytotrophoblasts. HLA-E was expressed weakly in synciciotrophoblasts and cytotrophoblasts and comparatively more strongly in extravillous cytotrophoblasts, essentially in parallel with total HLA-G.2. Antigen presenting ability of HLA-GTo investigate the ability, TAP dependency of HLA-G expression, and sequence of HLA-G bound peptide were examined. When HLA-G was isolated from transfected cells, a relatively large number of bound peptides derived from intra cellular proteins were identified, but the number of bound peptides was considerably smaller and the individual abundance considerably higher, with a single peptide species accounting for 15% of the total peptide bound to HLA-G from the placenta.