The Expression of Programmed Death-1 in Circulating CD4+ and CD8+ T Cells during Hepatitis B Virus Infection Progression and Its Correlation with Clinical Baseline Characteristics

BACKGROUND/AIMS: Programmed death-1 (PD-1) expression was investigated in CD4+ and CD8+ T cells from hepatitis B virus (HBV)-infected patients at the chronic hepatitis B (CHB) infection, liver cirrhosis (LC), and hepatocellular carcinoma (HCC) stages. METHODS: PD-1 expression in circulating CD4+ and CD8+ T cells was detected by flow cytometry. The correlations between PD-1 expression and HBV viral load, alanine aminotransaminase (ALT) levels and aspartate aminotransferase (AST) levels were analyzed using GraphPad Prism 5.0. RESULTS: PD-1 expression in CD4+ and CD8+ T cells was significantly increased in both the CHB group and advanced-stage group (LC plus HCC). In the CHB group, PD-1 expression in both CD4+ and CD8+ T cells was positively correlated with the HBV viral load, ALT, and AST levels. However, in the LC plus HCC group, significant correlations between PD-1 expression and the clinical parameters were nearly absent. CONCLUSIONS: PD-1 expression in peripheral CD4+ and CD8+ T cells is dynamic, changes with HBV infection progression, and is related to HBV viral load and liver function, especially in CHB. PD-1 expression could be utilized as a potential clinical indicator to determine the extent of virus replication and liver injury.

Expression of PD-1/PD-L1 in peripheral blood mononuclear cells in lung cancer patients and its biological significance / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To analyze the expression of co-stimulatory molecules PD-1/PD-L1 in peripheral blood mononuclear cells in lung cancer patients, and to explore its biological significance.</p><p><b>METHODS</b>One hundred and thirty-three lung cancer patients, 25 lung infection patients and 23 healthy donors were enrolled in this study. 100 µl of whole blood from these subjects were collected. Multi-color immunofluorescence staining and flow cytometry were used to detect PD-1/PD-L1 expression. The results were statistically analyzed.</p><p><b>RESULTS</b>The expression level of CD3⁺CD8⁺ T cells in the lung cancer patients was (38.83 ± 1.74)%, significantly lower than that in the control group [(43.25 ± 3.35)%, P < 0.05]. CD8⁺CD28⁺ T cell subset in the peripheral blood of lung cancer patients was (17.73 ± 1.21)% significantly lower than that of the healthy donors [(27.96 ± 2.72)%, P < 0.01]. The CD8⁺CD28⁻ T cell subset was (21.19 ± 1.92)% in the lung cancer patients, significantly higher than that of the healthy control group [(15.18 ± 2.93)%, P < 0.05]. The expression level of PD-1 on the surface of CD8⁺CD28⁺ T cells was (10.67 ± 1.12)% in the group of lung cancer patients, significantly higher than that of the control group [(5.32 ± 1.58)%, P < 0.01]. It was also found that the expression of PD-1 on CD8⁺CD28⁻ T cells was up-regulated in the group of lung cancer patients (7.46 ± 1.25)%, significantly higher than that of the healthy control group [(2.68+1.07)%, P < 0.01]. The expression level of PD-L1 on CD68⁺ cells in the lung cancer patients was (16.03 ± 2.06)%, significantly higher than that of the healthy control group [(9.32 ± 2.00)%, P < 0.05].</p><p><b>CONCLUSION</b>Up-regulation of PD-1/PD-L1 on peripheral blood cells in lung cancer patients negatively regulates the lymphocytes, inhibits the immune response for killing tumor cells, and promotes tumor development and immune escape.</p>

Effect of soluble PD-L1 released by lung cancer cells in regulating the function of T lymphocytes / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To explore the expression of soluble programmed death ligand-1 on lung cancer cells and to clarify its biological function through PD-1/PD-L1 pathway in regulating the function of T lymphocytes.</p><p><b>METHODS</b>Labeled monoclonal antibody and flow cytometry were used to analyze the expression of PD-L1 and its receptor PD-l on lung cancer cells and human T lymphocytes, respectively. The level of sPD-L1 in the supernatant of lung cancer cells was determined with an ELISA kit. The inhibition of proliferation of T lymphocytes by mPD-L1 and sPD-L1 was studied using CCK-8 incorporation.</p><p><b>RESULTS</b>Low or no expression [(16.08 ± 2.28)%] of PD-1 was found on resting T lymphocytes from human peripheral blood with flow cytometry, but up-regulated expression of PD-1 [(78.06 ± 7.21)%] was found on the surface of activated T lymphocytes. Soluble PD-L1 was found in supernatant of some lung cancer cell lines, such as H1299, HO8910, SPCA-1, H460, H446 cells, with PD-L1 expressing on their cell surface [(78.34 ± 10.25)%, (68.17 ± 11.56)%, (45.32 ± 7.98)%, (47.52 ± 9.62)% and (40.95 ± 8.56)%, respectively], but very low expression on A549 cells [(16.02 ± 6.28)%]. The level of mPD-L1 on H1299 cells was highest [(78.34 ± 10.25)%], compared with HO8910 cells (68.17 ± 11.56)%, SPCA-1 cells (45.32 ± 7.98)%, H446 cells (40.95 ± 8.56)%, and H460 cells (47.52 ± 9.62)%. At the same time, the sPD-L1 level on H1299 cells was low [(0.17 ± 0.01) ng/ml], compared with HO8910 cells (0.30 ± 0.03) ng/ml, SPCA-1cells (0.59 ± 0.03) ng/ml, H446 cells (0.34 ± 0.02) ng/ml, and H460 cells (0.57 ± 0.03) ng/ml, but not expressed on A549 cells. PD-L1 expressing H1299 cells inhibited the proliferation of T lymphocytes in the co-culture system. Supernatant of the cultured PD-L1(+) lung cancer cells also inhibited T cell proliferation. Anti-human PD-L1 blocking antibody could partly restore the proliferation capacity of T lymphocytes.</p><p><b>CONCLUSIONS</b>Membrane-bound PD-L1 and soluble PD-L1 released from lung cancer cells can effectively inhibit the proliferation of T lymphocytes in mixed culture system and down-regulate cell-mediated immunity in vitro. This may lead to inactivation of tumor antigen-specific T cells and immune escape of lung cancer cells.</p>

Construction of anti-CD28 single chain antibody genes and expression of the ScFv in BmN cells and the larvae of Bombyx mori / 生物工程学报

The V(H) and V(L) gene fragments of anti-CD28 mAb were combined to form anti-CD28 ScFv gene by using TP-PCR method. Sequence analysis showed that 6 x His tag was added to it for the ease of purification and the V(H), and V(L) gene fragments were connected by a linker containing 15 amino acids which are biased by the baculovirus promoter, ph. Then ScFv gene fragment was inserted into baculovirus transfer vector pBacPAK8. The recombinant transfer vector, pBacPAK8/CD28-ScFv was constructed successfully. The pBacPAK8/CD28-ScFv and the linear Bm-BacPAK6 were co-transfected into the cell line of Bombyx mori (BmN) with the help of Lipofectin,then the product was purified by plaque assay and identified by PCR method. The recombinant virus, Bm-BacPAK6 CD28-ScFv, was obtained successfully. The BmN cells and the larvae of Bombyx mori were infected by the recombinant baculovirus and harvested every 24h postinfection. SDS-PAGE and Western Blotting analysis confirmed the expression of ScFv with the molecular weight of about 28 kD. The expression in BmN cells was detected 24h post infection and it peaked at 72 h, while in the larvae of Bombyx mori, the expression was detected 48 h post infection and it peaked at 120 h.

Construction of a recombinant baculovirus transfer vector with two promoters expressing the anti-human CD28 chimeric antibody by using TP-PCR method / 生物工程学报

CD28, a cell surface glycoprotein, predominantly expressed on T cells, belongs to the Ig superfamily and provides critical co-stimulatory signals. The data which have published indicate that the monoclonal antibody against CD28 can decrease curative effects when it was applied in vivo for a long time. In order to avoid the human-anti-mouse action, anti-CD28 mAb must be humanized before it can be used in clinical study. Chimeric antibody, consisting of variable regions of mouse antibody and the constant regions of human IgG1, is often chosen by designers in generating humanized antibody. In this study, to prepare the anti-human CD28 chimeric antibody, the genes coding variable regions of anti-CD28 mAb and the constant regions of human IgG1 were cloned by PCR method. Then, the target genes were assembled by TP-PCR, a novel method developed for fusing genes without designing endonuclease sites at the both end of the target genes, and inserted into the baculovirus transfer vector pAcUW3 respectively. Thus, the recombinant baculovirus transfer vector with two strong promoters, ph and p10 was successfully constructed, which can express two different foreign genes at the same time. The recombinant vector was identified by the methods of restriction digesting, electrophoresis, PCR amplification and further verified by DNA sequence analysis. This work will contribute to expressing the chimeric CD28 antibody in insect cells.