Effect Of HLA-G Expressed In Platelets On HTLV-1 Viral Protein Tax

BackgroundHuman leukocyte antigen-G(HLA-G)is a non-classical major histocompatibility complex(MHC)class I molecule.As an immune tolerance molecule,HLA-G was initially found in placental trophoblast cells to provide immune tolerance for pregnant women and fetuses,but also to promote graft tolerance,reduce inflammatory response and immune response,and facilitate immune escape of tumor cells and viruses.Our previous study found that after HTLV-1 virus infected Hela and other tumor cells,the immune tolerance molecule HLA-G was highly expressed,which contributed to the transmission and infection of HTLV-1 virus.In recent years,studies have found that in addition to the role of anticoagulation and thrombosis,platelets are highly expressed in the blood of patients with a variety of malignant tumors,promoting the growth and metastasis of tumor cells and helping to evade the surveillance of the immune system.So,is there a relationship between platelets and immune tolerance molecule HLA-G in the process of malignant tumor development and virus infection? DoesHLA-G assist platelets to induce people with virus or tumor cells to escape host immune surveillance? In order to solve this scientific problem,we intend to observe the expression of HLA-G on platelets and study the immunomodulatory effect of platelets on HTLV-1 infection.ObjectiveTo observe the expression of human leukocyte antigen G(HLA-G)on platelets and to study the immunomodulatory effect of HLA-G on HTLV-1 infection.Methods1.Flow cytometry detection of platelet membrane type mhla-g: venous whole blood was collected,platelets were separated,and fluorescence staining of platelets was performed with HLA-G specific antibody.The expression of platelet membrane type mhla-g was detected by flow cytometry.2.Detection of secretory sHLA-G in platelet lysate by ELISA: the whole venous blood was collected aseptically,the serum was separated from non anticoagulant whole blood,the concentrated platelets were separated from EDTA-K2 whole blood,and then diluted into different concentrations of platelet solution with normal saline,and the number of platelets in different dilutions of platelet solution was detected by Mindray bc5800 blood routine analyzer,Platelet lysate(PL)was prepared by freezing platelets of different concentrations diluted with normal saline at-80 ℃ and thawing at 37 ℃ for three cycles.The expression of secretory sHLA-G in serum and different concentrations of platelet lysate was detected by ELISA.3.Western blot was used to detect the effect of HLA-G expressed in platelets on HTLV-1 viral protein tax: MT2 cells stably infected with HTLV-1 were cultured in 1640 medium.(1)control group: cells were cultured in 10% fetal bovine serum medium;(2)Experimental group: cells were cultured in 10% PL medium;(3)Antibody blocking group:20 ng / ml anti HLA-G antibody(16913-1-ap)was added into 10% PL medium to culture MT2 cells.Western blot was used to detect the effect of HLA-G on the expression of HTLV-1 virus protein tax.Results1.high expression of mhla-g on platelets: it was found that mhla-g was highly expressed on platelets by flow cytometry.The platelet mhla-g in experimental group was significantly higher than that in the control group [(56.90)± 2.58)% vs(1.083 ±0.39 The difference was statistically significant(P < 0.01);There was no significant difference between the blank control group and the same type control group.2.the content of sHLA-G in platelet lysate was significantly increased: it was found that the serum contained very small amount of sHLA-G by ELISA,and a small amount of sHLA-G in the platelet rich plasma(PRP),which was significantly higher than that of serum,and the difference was statistically significant(P < 0.01).After platelet lysis,the content of sHLA-G increased obviously,with the increase of platelet concentration,the content of sHLA-G increased,which showed dose-dependent effect.3.HLA-G promotes the expression of the HTLV-1 virus protein,which is found by Western blot.Compared with fetal bovine serum,MT2 cells cultured in platelet lysate have high expression of TOX and HLA-G protein,and the expression of tax egg white in MT2 cells can be reduced significantly after anti HLA-G antibody and HLA-G in the lysate.ConclusionPlatelets with high expression of immune tolerance molecule HLA-G,and the expression of HLA-G contribute to the infection of HTLV-1 virus.