The Soluble HLA-G Dimer Can Inhibit The Maturation Of Dendritic Cell And The Polarization Of M1Macrophage In Vitro

HLA-G, a non-classical HLA class I molecule, induces a wide range of tolerogenicimmunological effects via interaction with its inhibitory receptors. Soluble HLA-G dimer hasstronger binding force with its receptors and exhibits its effects than HLA-G. These receptors，including ILT-4and ILT-2,express on the surface of T cell, B cell, macrophage, NK, DC, and soon. DC are the most potent antigen-presenting cells for linking the innate to the adaptive immuneresponses.They detect, capture and process foreign antigens and present them to T cells. Theirinteractions with na ve T cells play important role for directing T cell differentiation towardTh1/Th2polarization and regulatory T cells. Many reports have proved that the soluble HLA-Gdimer can inhibit the maturation of DC by binging with ILT4recently, but some reports provedthat the soluble HLA-G dimer has no affection on the maturation of DC. Our study will discussthe influence of the soluble HLA-G dimer on the maturation of DC. It’s hoped that this dimer caninhibit the maturation of DC and further induce the immune tolerance of T, B cell, reduce theextent of transplant rejection reaction. Macrophages involve and promote inflammatory response.They can be sorted as classical activation pattern and alternative activation M2according to theirmicroenvironment. The former has relationship with inflammation and tissue destruction; thelatter promotes angiogenesis and tissue repair, involves in the immune response to parasite,allergy. And they can convert into each other under certain conditions. Because the solubleHLA-G dimer receptors are expressed on the surface of macrophage, our study will discuss the influence of the soluble HLA-G dimer on the differentiation of these two kinds of cells, explorethe role of the soluble HLA-G dimer in inflammatory response. This work contains the followingtwo major parts:1. The soluble HLA-G dimer can inhibit the maturation of DC in vitroPBMC were isolated from human peripheral blood, adherent monocyte were induced intoimmature DC with GM-CSF, IL-4and TNF-or IFN-γ can promote the mature of DC. At thesame time, the soluble HLA-G dimer or the supernatant of721.221were added into experimentalgroup. Cells were collected and dyed with immunofluorescence antibody CD1a, CD83andCD40.The expression levels of these molecules were performed using flow cytometry. The testresults showed that the expression levels of CD83and CD40on DC with soluble HLA-G dimerwere lower than the group of supernatant of721.221.2. The soluble HLA-G dimer can inhibit the polarization of M1in vitroPBMC were isolated from human peripheral blood. M1were obtained from adherentmonocyte with GM-CSF and LPS. M2were obtained with M-CSF and IL-4. The soluble HLA-Gdimer or the supernatant of721.221were added during this process. Cells were scraped and dyedwith immunofluorescence antibody CD14, CD206and CD80. The expression levels ofCD14+CD80+on M1and CD14+CD206+on M2were performed using flow cytometry. The testresults showed that the soluble HLA-G dimer can downregulate the expression of CD80on thesurface of M1, but has no affection towards the expression of CD206on the surface of M2.