Kinetics of phytohemaglutinin-induced IFN-γ and TNF-α expression in peripheral blood mononuclear cells from patients with chronic hepatitis B after liver transplantation

Cytokines in Liver Transplantation

Cytokines, soluble mediators of the immune system, play a critical role in the pathogenesis of autoimmune, allergic and infectious diseases. They are also implicated in the initiation and development of allograft rejection. During recent years, there have been considerable advances in generating novel anti-cytokine agents with promoted efficacy and safety, which could be administrated for managing dysregulated cytokine secretion; besides, gene therapy for overexpression of immunomodulatory cytokines has shown substantial improvements. Liver transplantation has been established as a life-saving treatment for end-stage hepatic diseases but the growing number of recipients urge for improved post-transplant care including tolerance induction, infection control and resolving immunosuppressant drugs adverse effects. Cytokines with a wide range of proinflammatory and regulatory properties might be considered as potential therapeutic targets for selective suppression or enhancement of the immune responses in recipients. In the present review, we aimed to summarize the positive and negative effects of cytokines on liver allograft in addition to their prognostic and therapeutic values.

Probable involvement of p11 with interferon alpha induced depression

Depression is one of the major side effects of interferon alpha (IFN-α) treatment, but the molecular mechanism underlying IFN-α-induced depression remains unclear. Several studies have shown that the serotonin receptors 5-HTR1b and 5-HTR4 play key roles in the anti-depression effects associated with p11 (S100A10). We investigated the effects of IFN-α on the regulation of p11, 5-HTR1b and 5-HTR4 in mice and human neuroblastoma cells (SH-sy5y). We found that intraperitoneal injection with IFN-α in Balb/c mice resulted in an increased immobility in FST and TST, and potently lowered the protein levels of p11, 5-HTR1b and 5-HTR4 in the hippocampus or cingulate gyrus. IFN-α significantly down-regulated the protein levels of p11, 5-HTR1b and 5-HTR4 in SH-sy5y cells, in a time- and dose-dependent manner. Our study revealed that over-expression of p11 could prevent the IFN-α-induced down-regulation of 5-HTR1b and 5-HTR4. The results indicated that IFN-α treatment resulted in p11 down-regulation, which subsequently decreased 5-HTR1b and 5-HTR4 in vitro or in vivo. Our findings suggested that p11 might be a potential regulator on 5-HTR1b and 5-HTR4 as well as a predictor of or a therapeutic target for IFN-α-induced depression.

Impaired antigen processing and presentation machinery is associated with immunotolerant state in chronic hepatitis B virus infection

BACKGROUND AND AIMS

The mechanism of hepatitis B virus (HBV)-specific T cell hyporesponsiveness in hepatitis Be antigen (HBeAg)-positive subjects is not well understood. Inefficient antigen processing and transport to major histocompatibility complex class I molecules, namely due to low molecular weight protein (LMP) 2 and 7 and transporter associated with antigen processing (TAP) 1 and 2 genes could be playing a role.

PATIENTS AND METHODS

Forty patients with chronic hepatitis B (CHB) infection, hepatitis B surface antigen, and HBeAg positive; 26 with raised (Gr. I) and 14 with persistently normal ALT levels (Gr. II) and 11 healthy controls (Gr. III) were studied. Total RNA was isolated from peripheral blood mononuclear cells and mRNA expression of TAP1, TAP2, LMP2, and LMP7 genes was analyzed by semi-quantitative reverse transcriptase-polymerase chain reaction method. Gamma interferon (IFN-gamma) and tumor necrosis factor-alpha (TNF-alpha) levels were quantified by enzyme-linked immunosorbent assay (ELISA) using log-log and linear graphs, respectively.

RESULTS

Group II CHB patients had significantly lower mRNA expression for TAP1 (p = 0.003) and LMP2 (p = 0.002) genes as compared to Gr. I patients. The mRNA expression of TAP2 and LMP7 genes was comparable between the groups. However, expression of TAP1 (p = 0.02), TAP2 (p = 0.035), and LMP2 (p = 0.041) was found to be significantly higher in Gr. III subjects compared to Gr. I and Gr. II patients. In Gr. I and II, the IFN-gamma {s54.2{9.4-165} pg/ml), (59.5{28.5-110} pg/ml)}, and TNF-alpha {12.0 (8.0-23.2)},{10.8(6.2-20.8)} pg/ml levels were comparable but were significantly (p = 0.00,0.004, respectively) higher than Gr. III subjects.

CONCLUSIONS

Low expression of TAP1 and LMP2 suggests an important role of these genes in defective viral antigen processing in immune tolerant state of CHB patients. Higher IFN-gamma and TNF-alpha production in CHB are probably enough to potentiate liver injury but not enough to clear the chronic HBV infection. These novel observations could pave way for new therapeutic strategies for immune restoration in CHB infected patients.

Increased apoptosis in HepG2.2.15 cells with hepatitis B virus expression by synergistic induction of interferon-gamma and tumour necrosis factor-alpha

BACKGROUND

Interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) were thought to be important immune mediators in host defence against hepatitis B virus (HBV) infection.

AIMS

To examine the synergistic effect of IFN-gamma and TNF-alpha on HBV-expressing HepG2.2.15 cells and its potential mechanisms.

METHODS

Cell viability was quantitatively measured by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide assay. Cell morphology was captured using light microscopy. The typical DNA ladder test was performed using agarose gel electrophoresis. HBsAg and HBeAg titre changes were quantified by the enzyme-linked immunosorbent assay method. Gene expression was analysed using cDNA macroarrays.

RESULTS

Interferon-gamma (1000 U/ml) alone or combined with TNF-alpha (5 ng/ml) treatment resulted in apoptosis in HepG2.2.15 cells, but no significant apoptosis in the parent non-virus expressing HepG2 cells. IFN-gamma- and TNF-alpha-mediated apoptosis was reduced by lamivudine treatment in HepG2.2.15 cells. IFN-gamma combined with TNF-alpha reduced the titre of hepatitis B surface antigen and hepatitis B e antigen in the HepG2.2.15 cell line. For apoptosis-related gene changes, IFN regulatory factor 1 (IRF-1) (12.2-fold), c-myc (V00568 4.7-fold, L00058 2.4-fold) and caspase 7 (2.3-fold) genes were upregulated in the combination treatment group.

CONCLUSION

Interferon-gamma and TNF-alpha play a role in the cell death of HBV-expressing HepG2.2.15 cells. Expression of HBV leads to IFN-gamma- and TNF-alpha-mediated apoptosis in the cells. Increased IRF-1, c-myc and caspase 7 gene expression may be responsible for the synergistic induction of apoptosis by IFN-gamma and TNF-alpha.

The in vitro antitumor effect and in vivo tumor-specificity distribution of human-mouse chimeric antibody against transferrin receptor

Transferrin receptor (TfR/CD71) deserves attention as a selective target for cancer therapy due to its higher expression in tumors versus normal tissues. Also, it has been shown the mouse-derived monoclonal antibody against TfR can significantly inhibit the proliferation of tumor cells. Through constructing the chimeric antibody against TfR, the antigenicity of antibody can be weakened, and most importantly, the antitumor effect of antibody can be strengthened by the introduction of the human Fc fragment. In previous studies, we successfully constructed the human-mouse chimeric antibody against TfR (D2C) and demonstrated that its Fab fragment could specially recognize the TfR on the surface of target cells. In this study, through labeling the chimeric antibody D2C with 125I, we calculated the affinity constant (Ka) of 9.34-9.62x10(9) l/mol for this antibody according to the Scatchard drawing method. Moreover, in vivo studies in nude mice-bearing human liver cancer (SMMC-7721) xenografts have shown that the radioactivity distribution ratio of 131I-D2C on T/NT was 2-14:1 or 3-21:1 on the seventh day after intraperitoneal or intratumoral injection of 131I-labeled D2C (131I-D2C). These evidences indicated that the in vivo distribution of D2C display the characteristics of certain tumor-specificity localization. In vitro studies, D2C can induce the apoptosis of K562 through the mitochondria death pathway and arrest the cell at G1 phase, as determined by cell cycle analysis. Using the human tumor cells (K562, CEM, and SMMC-7721) expressing TfR as target cells, and normal human PBMC as effector cells, Fc fragment of D2C can perform both the antibody-dependent cell-mediated cytotoxicity and the complement-dependent cytotoxicity. Together, it was demonstrated that the D2C display a tumor-specificity distribution, and has a strong antitumor effect. Thus, it has the potential therapeutic significance.