Preliminary results of Thymosin-a1 vs interferon-α treatment in patients with HBeAg negative and serum HBV DNA positive chronic hepatitis B

H3K9 acetylation modification and TLR9 immune regulation mechanism in patients after anti-HBV treatment

To improve the curative effect of anti-hepatitis B virus (HBV) drugs, methods such as thymosin and entecavir combination have become a focus of clinical investigation. The aim of this retrospective experimental study was to explore the potential mechanism of action of thymosin a1 (Ta1) combined with entecavir in the treatment of HBV infection. A total of 28 patients with chronic hepatitis B, 29 patients treated with thymosin a1 and entecavir combination, and 15 healthy individuals were enrolled in this study. RT-qPCR was conducted to evaluate the mRNA levels of TLR9 in peripheral blood mononuclear cells (PBMCs). The serum level of TLR9 protein was analyzed by ELISA. The binding of TLR9 gene to the protein H3K9Ac in PBMCs was assessed by chromatin immunoprecipitation, and serum inflammatory factors were detected by Luminex technology. The expression levels of TLR9 mRNA and serum TLR9 protein in patients with HBV infection were significantly lower than those in subjects in the control group before treatment but increased after treatment with the Ta1 and entecavir combination. Moreover, the acetylation protein H3K9Ac was significantly bound to the promoter region of the TLR9 gene in patients with HBV infection treated with the Ta1 and entecavir combination compared to that in patients with HBV infection without treatment. Furthermore, the expression levels of interleukin 6 (IL-6), interleukin 12 (IL-12), interferon gamma, and necrosis factor alpha in patients with HBV infection after the combination treatment were slightly decreased compared to those in patients with HBV infection without treatment. In conclusion, the histone acetylation modification of TLR9 was significantly improved in patients with HBV infection after treatment with the Ta1 and entecavir combination, which elevated the expression of TLR9 at the mRNA and protein levels and further regulated the expression of IL-6, IL-12, and other cytokines.

Historical review of thymosin α 1 in infectious diseases

INTRODUCTION

Thymosin α 1 (Tα1) is a peptidic biological response modifier, which plays a significant role in activating and regulating various cells of the immune system. For the above-mentioned activities it is expected to exert a clinical benefit in the treatment of diseases where the immune system is altered.

AREAS COVERED

Several clinical trials have been carried out with Tα1 for treatment or prevention of many different infectious diseases such as hepatitis B and C, sepsis and Aspergillosis in bone marrow-transplanted patients. Data available on the use of Tα1 in infectious disease as well as a vaccine enhancer will be reviewed to possibly generate new working hypothesis.

EXPERT OPINION

Tα1 has been widely used in thousands of patients. Nevertheless, there are some issues that have not yet been properly addressed (i.e., dose, schedule, combination treatments, end-points to be evaluated in clinical trials). In the most recent clinical trials Tα1 has been used at higher doses than those commonly used in the past showing a direct proportionality between the dose and the effect. The safety profile of Tα1 is excellent and it is virtually devoid of toxicity.

Cloning and functions of the HBxAg-binding protein XBP1

In the present study the hepatitis B virus X antigen binding protein 1 (XBP1) was cloned by inducing its expression, and its subcellular localization and function were examined. Total RNA was extracted from HepG2 cells and XBP1 was amplified using reverse transcription polymerase chain reaction (RT-PCR), followed by restriction enzyme digestion of the pGBKT7 yeast plasmid and identification by enzyme digestion. The plasmid was transformed into AH109 yeast via the lithium acetate method and protein extracts were prepared. XBP1 protein expression in the eukaryotic cells was determined using polyacrylamide gel electrophoresis and western blot analysis. The gene encoding the XBP1-binding protein was screened in liver cells using yeast two-hybrid technology. We transfected a human hepatocellular carcinoma cell line and observed the intracellular localization of the gene expression protein using a fluorescence microscope, followed by prokaryotic expression and XBP1 gene identification. A 921-bp XBP1 gene fragment was obtained via RT-PCR amplification and 20 proteins with known functions that interact with XBP1 were screened, including metallothionein, smooth muscle cell-related protein, asialoglycoprotein receptor, pyruvate dehydrogenase kinase 1 and a sequence with unknown functions. A green fluorescent protein expression plasmid pEGFP-C1-XBP1 of XBP1 was constructed successfully and its expression protein was localized in the cytoplasm. A 56-kDa recombinant protein was successfully obtained via prokaryotic expression and was demonstrated to have good specificity using western blot analysis. The XBP1 gene, which expresses the XBP1 protein, is located in the cytoplasm and plays a role in the intracellular structure, cell growth, intracellular metabolism and signal transduction pathway, as well as DNA duplication, transcription, recombination and repair.

Efficacy of thymosin α-1 plus peginterferon α-2a combination therapy compared with peginterferon α-2a monotherapy in HBeAg-positive chronic hepatitis B: a prospective, multicenter, randomized, open-label study

OBJECTIVE

Thymosin α-1 plus interferon α-2a offers superior efficacy over interferon α-2a alone in patients with chronic hepatitis B. The aim was to compare the antiviral efficacy of thymosin α-1 plus peginterferon α-2a and peginterferon α-2a alone in HBeAg-positive chronic hepatitis B patients.

MATERIALS AND METHODS

HBeAg-positive CHB patients were enrolled in this prospective, randomized, open-label study. Fifty-one patients were assigned to either combination (26 patients; 180 μg of peginterferon α-2a weekly for 48 weeks and 1.6 mg of thymosin α-1 twice a week for the first 12 weeks) or monotherapy (25 patients; 180 μg of peginterferon α-2a weekly for 48 weeks) groups.

RESULTS

The rates of the combined response, defined as HBeAg seroconversion, HBV DNA suppression, and normalization of serum ALT, were 4/26 (15.4%) and 3/25 (12.0%) for the combination group and the monotherapy group at the end of treatment (p = 0.725), and 6/26 (23.1%) and 5/25 (20.0%) at the end of follow-up (p = 0.789), respectively. Based on multiple logistic regression analysis, a >2 log₁₀ IU/mL reduction of HBV DNA at week 12 was identified as an independent predictor for combined response (OR, 9.72; 95% CI, 1.33-71.06; p = 0.025) at the end of follow-up. A lower pretreatment HBV DNA level (≤ 7 log(10) IU/mL) was another predictor for combined response (OR, 9.64; 95% CI, 1.23-75.32; p = 0.031). No significant differences in adverse events were observed.

CONCLUSIONS

The short-term addition of thymosin α-1 was not superior to peginterferon α-2a alone in HBeAg-positive CHB patients on the basis of antiviral efficacy.

Thymalfasin in the treatment of hepatitis B and C

Thymalfasin exhibited an immunomodulatory and a direct antiviral mechanism of action. The low rate of sustained response of chronic hepatitis with current therapies, underscores the need for new therapeutic options. It has been suggested that thymalfasin may have efficacy in the treatment of chronic hepatitis B and C. Pilots studies in patients with chronic hepatitis B treated with thymalfasin in combination with interferon or nucleoside analogue, showed a 70% complete sustained response rate. Studies in chronic hepatitis C patients, would indicate that thymalfasin in combination with standard or pegylated interferon with ribavirin may improve response rate in hepatitis C virus (HCV) naïve and nonresponder patients. However, a large phase-III randomized study conducted in Europe in HCV patients nonresponder to Peg-interferon with ribavirin, demonstrated that thymalfasin did not improve the rate of sustained virologic responses, but, in patients who completed therapy, thymalfasin significantly diminished the relapse rate. In conclusion, thymalfasin, in combination with the standard of care, may be helpful as an adjuvant in the treatment of patients with chronic hepatitis B and C.

[Treatment of hepatitis B: new perspectives]

Despite the development of new anitiviral agents, the treatment of chronic hepatitis B remains a major clinical challenge. Major achievements have been made with the rationale use of antivirals exhibiting a complementary cross resistance profile to prevent antiviral drug resistance. The current concept of modern antiviral therapy of chronic hepatitis B relies on a precise virologic monitoring and early treatment adaptation to prevent drug resistance. The difficulty of achieving viral clearance and the risk of drug resistance development are major arguments to continue research in the field of antivirals and to identify new targets for therapy. The development of true combination therapy is highly desirable to fulfil the objective of long-term viral suppression, clearance of viral cccDNA and infected cells and ultimately cure of the disease.

Comparison of the efficacy of thymosin alpha-1 and interferon alpha in the treatment of chronic hepatitis B: a meta-analysis

Chronic hepatitis B virus (HBV) infection is a serious problem because of its worldwide distribution and possible adverse sequelae, such as cirrhosis and hepatocellular carcinoma. Thymosin alpha-1 (Talpha1) is an immune modifier that has been shown to be effective for chronic hepatitis B (CHB) in some trials. But the trials comparing Talpha1 vs. interferon alpha (IFNalpha) treatment in CHB have been small and the results have been inconsistent. So we conducted a meta-analysis to compare the efficacy of Talpha1 and IFNalpha in the treatment of CHB. Generally, four randomized controlled trials including 199 CHB patients who received Talpha1 or IFNalpha treatment were identified through MEDLINE and EMBASE online search. Virological (for hepatitis B e antigen (HBeAg) positive patients, loss of HBV DNA and HBeAg; for HBeAg negative patients, loss of HBV DNA), biochemical (normalization of transaminases) and complete responses (fulfill criteria of biochemical and virological response simultaneously) were analyzed using the intention-to-treat method. The odds ratio (OR) was used to measure the magnitude of the efficacy. The ORs (95% confidence interval) of the virological response, biochemical response and complete response of Talpha1 over IFNalpha at the end of 6 months treatment were 0.62 (0.35, 1.10), 0.60 (0.34, 1.05) and 0.54 (0.30, 0.97), respectively. The ORs (95% confidence interval) of the virological response, biochemical response and complete response of Talpha1 over IFNalpha at the end of follow-up (6 months post-treatment) were 3.71 (2.05, 6.71), 3.12 (1.74, 5.62) and 2.69 (1.47, 4.91), respectively. These data showed that compared with IFNalpha, the benefit of Talpha1 was not immediately significant at the end of therapy, but virological, biochemical and complete response had a tendency to increase or accumulate gradually after the therapy. For three of the four trials that studied HBeAg-negative patients, the results are mostly applicable to HBeAg-negative CHB.

Thymosin Alpha 1: From Bench to Bedside

After the initial dramatic effects, observed in a Lewis lung carcinoma animal model, using a combination of thymosin alpha 1 (Talpha1) and interferon (IFN) after cyclophosphamide, a number of other preclinical models in mice (Friend erythroleukemia and B16 melanoma) and in rats (DHD/K12 colorectal cancer liver metastasis) have confirmed the efficacy of the combination therapy with Talpha1 and either IFN or IL-2 plus chemotherapy. These results provided the scientific foundation for the first clinical trials using Talpha1 in combination with BRMs and/or chemotherapy. Pivotal trials in advanced non-small cell lung cancer (NSCLC) and melanoma with Talpha1 and IFN-alpha low doses after cis-platinum or dacarbazine produced the first evidence of the high potentiality of this approach in the treatment of human cancer. The combination of Talpha1 and IFN-alpha was also used in patients affected by chronic B and C hepatitis including IFN-nonresponders and infected by precore mutants or genotype 1b. Further studies demonstrated additional biological activities clarifying the mechanism of action of Talpha1, partially explaining the synergism with IFN. It has been shown the capacity of activating infected dendritic cells through Toll-like receptor signaling, thus influencing the inflammation balance, and of increasing the expression of tumor, viral, and major histocompatibility complex (MHC) I antigens. Dose-response studies suggested the possibility of improving the efficacy of this molecule reducing the overall toxic. Based on these information two clinical trials are ongoing: a large phase II on advanced melanoma patients treated with Talpha1 at different doses after dacarbazine and a phase III one, on IFN-resistant hepatitis C virus (HCV) patients treated with a triple combination (IFN, ribavirin, and Talpha1).

Hepatitis B virus genotype B is associated with better response to thymosin alpha1 therapy than genotype C

Hepatitis B virus (HBV) genotype has been reported to correlate with response to interferon treatment in several studies. The relationship between HBV genotype and thymosin alpha1 (T-alpha1) treatment is unknown. We retrospectively examine HBV genotypes, precore and core promoter mutations in patients treated with Talpha1 and analyse the correlation between complete response [alanine aminotransferase (ALT) normalization plus seroclearance of HBeAg and HBV-DNA] and HBV genotype. It consisted 98 patients with chronic hepatitis B randomly allocating to three groups: (i) T6 group (n = 32) received a 26-week course of Talpha1 1.6 mg two times a week; (ii) T12 group (n = 34) received the same regimen as T6 group, but Talpha1 therapy extended for 52 weeks; (iii) T0 group (n = 32) served as a control and was followed up for 18 months without specific treatment. Stepwise logistic regression analysis showed that genotype (OR, 3.747; 95% CI, 1.066-13.170; P = 0.039), precore mutation (OR, 6.285; 95% CI, 1.874-21.086; P = 0.003) and Talpha-1 treatment (OR, 12.045; 95% CI, 2.220-65.354; P = 0.004) as independent factors associated with complete response. The complete response of Talpha-1 therapy was higher in patients with genotype B compared to patients with genotype C (52%vs 24%; P = 0.036) and in patients with precore mutation (64%vs 19%; P = 0.002). In conclusion, genotype, presence of precore mutation and Talpha-1 therapy were independent predictors to complete response. Genotype B, compared to genotype C, is associated with a higher response rate to T-alpha1 therapy.

The efficacy and safety of thymosin alpha-1 in Japanese patients with chronic hepatitis B; results from a randomized clinical trial

Thymalfasin (thymosin alpha-1; Talpha1) is a 28-amino acid polypeptide that has shown efficacy in the treatment of chronic hepatitis B virus (HBV) infection. The objective of this study was to evaluate the long-term, dose-related efficacy and safety of Talpha1 treatment in chronic hepatitis B patients with positive HBV-DNA and abnormally high alanine aminotransferase (ALT) levels. A total of 316 patients were randomized to receive either 0.8 or 1.6 mg of Talpha1 monotherapy for 24 weeks. At the end of the 72-week observation period (12 months after cessation of therapy), 36.4% of patients in the 1.6-mg treatment group achieved normalization of ALT, 30% achieved clearance of HBV-DNA by branched DNA vs 15% by transcription-mediated amplification, and 22.8% achieved clearance of HBe-antigen. Patients in the 0.8-mg treatment group achieved similar efficacy rates, although patients with advanced fibrosis demonstrated a significantly better response rate when treated with 1.6 mg of Talpha1 monotherapy vs 0.8 mg (as determined by intragroup analysis; patients were not stratified by liver biopsy). All adverse drug reactions were mild and most involved the fluctuation of liver enzymes, which was most likely related to the positive immune effects caused by the response to Talpha1 treatment. Adverse event incidence was similar in the 1.6- and 0.8-mg treatment groups. In conclusion, Talpha1 at doses of 0.8 and 1.6 mg exhibits long-term efficacy against hepatitis B with a good safety profile.

Identification of the immunogenic domains in HBsAg preS1 region using overlapping preS1 fragment fusion proteins

AIM: The incorporation of hepatitis B virus (HBV) preS1 region into epitope-based vaccines against HBV has been accepted widely, but the incorporate site and size of preS1 sequence is controversial. Therefore our purpose was to further investigate its immunogenic domains for the epitope-based hepatitis B vaccine design.

METHODS: Eight GST fusion proteins containing overlapping preS1 fragments in preS1 (21-119) region were expressed in E.coli. Using these purified fusion proteins, the immunogenic domains in preS1 region were identified in detail in mice and humans by Western blot analysis and ELISA.

RESULTS: The results in mice showed that the immu-nogenic domains mainly existed in preS1 (21-59) and preS1 (95-109). Similarly, these fragments had strong immunogenicity in humans; whereas the other parts except for preS1 (60-70) also had some immunogenicity. More importantly, a major immunogenic domain, preS1 (34-59), which has much stronger immunogenicity, was identified. Additionally, the antibodies against some preS1 fragments, especially preS1 (34-59), were speculated to be virus-neutralizing.

CONCLUSION: Eight GST fusion proteins containing overlapping preS1 fragments were prepared successfully. They were used for the study on the immunogenic dom-ains in preS1 (21-119) region. The preS1 (34-59) fragm-ents were the major immunogenic domains in the preS1 region, and the antibodies against these fragments were speculated to be virus-neutralizing. Therefore, the incorporation of preS1 (34-59) fragments into epitope-based HBV vaccines may be efficient for enhancement of immune response. Additionally, the results also imply that there are more complex immune responses to preS1 region and more abundant immunogenic domains in humans.

Emerging treatments in chronic hepatitis B

Although the management of chronic hepatitis B has improved over the last decade, none of the available therapeutic agents, IFN-alpha, lamivudine and adefovir dipivoxil, can achieve sustained off-therapy responses in most cases. Therefore, several newer, mainly antiviral and immunomodulatory agents, are being evaluated. Pegylated IFN-alpha(2a) has been shown to be more effective than lamivudine or standard IFN-alpha monotherapy in achieving post-therapy biochemical and virological responses, and is expected to be licensed soon for the treatment of chronic hepatitis B. Newer antiviral agents, such as entecavir and telbivudine, appear to be quite effective initially, but their sustained off-therapy response rates remain unknown. The preliminary data of monotherapies with immunomodulatory agents, or of combination therapies, have been rather disappointing. Long-term maintenance treatment with antiviral agent(s) with good safety and tolerability profiles and low resistance rates appears to be the most realistic future therapeutic option for most chronic hepatitis B patients.

Thymalfasin (thymosin-alpha 1) therapy in patients with chronic hepatitis B

Chronic hepatitis B virus (HBV) infection is a serious clinical problem because of its worldwide distribution and potential adverse sequelae. Globally, there are approximately 350 million people infected with chronic HBV, 75% of whom live in the Asia-Pacific region. Interferon-alfa and direct antiviral agents such as lamivudine and adefovir are effective in the therapy of chronic HBV infection but the efficacy is far from satisfactory, particularly in perinatally infected patients, patients with lower ALT levels and those with HBeAg-negative chronic hepatitis B. Thymalfasin (thymosin-alpha1) is an immunoregulatory agent able to enhance Th1 response. It has been shown to trigger maturational events in lymphocytes, to augment T-cell function, and to promote reconstitution of immune defects. Studies are underway in both monotherapy and combination therapy with thymalfasin and interferon and results are promising.

Rapid and high throughput detection of HBV YMDD mutants with fluorescence polarization

AIM: To develop a simple and rapid detection of HBV gene variants and prediction of lamivudine-resistance in patients.

METHODS: Initially, plasmids harboring the wild-type or mutant HBV DNA fragments were used in a model system. The technique was then applied to clinical samples for an analysis of YMDD mutations. The sera were extracted from chronic hepatitis patients who had received lamivudine treatment for more than one year. P region gene of HBV was amplified by polymerase chain reaction. The excess primers and dNTPs in PCR products were removed by cleaning-up reagents. Template-directed dye-terminator incorporation reaction was performed and R110 or TAMRA labeled acyclo-terminator was added on the 3’ end of TDI-primer specifically. Fluorescence polarization value was measured with Victor 2 multilabel counter and the genotypes of HBV were analyzed.

RESULTS: The YMDD genotypes in recombined positive plasmid and 56 serum samples of HBV infected patients were analyzed by using our TDI-FP method and the specificity and sensitivity were confirmed by DNA sequencing. Five of 56 serum samples showed YVDD phenotype (9%), including 1 YMDD and YVDD mixed infection. Four of 56 showed YIDD phenotype (7.1%).

CONCLUSION: This is a simple, rapid, low cost and high throughput assay to detect HBV polymerase gene variants and suitable for large-scale screening and prediction of the lamivudine-resistance in clinical samples.

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Anti-HBV effect of TAT- HBV targeted ribonuclease

AIM: To prepare and purify TAT-HBV targeted ribonuclease fusion protein, evaluate its transduction activity and investigate its effect on HBV replication in 2.2.15 cells.

METHODS: The prokaryotic expression vector pTAT containing TR gene was used in transforming E.coli BL21 (DE3) LysS and TR was expressed with the induction of IPTG. The TAT-TR fusion protein was purified using Ni-NTA-agrose and PD-10 desalting columns, and analyzed by SDS-PAGE. Transduction efficiency of TAT-TR was detected with immunofluorescence assay and the concentration of HBeAg in the supernatant of the 2.2.15 cells was determined via solid-phase radioimmunoassay (spRIA). MTT assay was used to detect the cytotoxicity of TAT-TR.

RESULTS: The SDS-PAGE showed that the TAT-TR fusion protein was purified successfully, and the purity of TAT-TR was 90%. The visualization of TAT-TR by immunofluorescence assay indicated its high efficiency in transducing 2.2.15 cells. RIA result suggests that TAT-TR could inhibit the replication of HBV effectively, it didn’t affect cell growth and had no cytotoxicity.

CONCLUSION: TAT-TR possesses a significant anti-HBV activity and the preparation of TAT-TR fusion protein has laid the foundation for the use of TR in the therapeutic trial of HBV infection.

Correlation of splenic ultrasonography, HBV e system and AFP levels in hepatitis B with hepatic fibrosis and carcinogenesis

AIM

To clarify the relationship of splenic ultrasonography in liver fibrosis and carcinogenesis associated with hepatitis B, the spontaneous conversion of HBeAg to Anti-HBe and AFP level.

METHODS

The indexes of spleen ultrasonography of liver fibrosis along with carcinogenensis related with hepatitis B, positive rates of HBeAg or Anti-HBe and AFP levels were compared in different liver fibrosis stages and hepatocellular carcinoma (HCC) related with hepatitis B.

RESULTS

The lengths of spleen (mm) in stages of liver fibrosis S1, S2, S3, S4 and HCC with hepatitis B were 104.6±13.1, 108.7±13.6, 110.5±15.4, 123.0±16.8 and 116.9±28.2, respectively; differences of splenic length between group S4 and groups S1, S2 or S3 were significant statistically (P<0.05). The thicknesses of spleen (mm) in groups S1, S2, S3, S4 and HCC were 35.2±6.3, 37.0±7.7, 37.8±9.6, 43.3±10.8 and 40.811.2, respectively; difference in splenic thickness between group S4 and S1 was significant statistically (P<0.05). The widths of splenic vein (mm) in groups S1, S2, S3, S4 and HCC were 6.0±1.4, 6.5±1.4, 6.8±1.7, 7.8±1.7 and 6.82.6 respectively; there were differences among groups S4 and S1 or S2 (P<0.05) statistically. The positive rates of HBeAg were 92%(23/25), 75.6%(31/41), 68.8%(22/32), 51.9%(14/27) and 13.5%(5/37); and the positive rates of anti-HBe were 4%(1/25), 19.5%(8/41), 25%(8/32), 33.3%(9/27) and 70.3%(26/37) in group S1, S2, S3, S4 and HCC, respectively; difference between each two group among group S1, S2, S3, S4 and HCC was significant(P<0.05). The AFP levels(μg/L) were 11.0±6.7, 49.4±74.5, 112.11±59.0, 179.32±0.8 and 367.46±17.1 in group S1, S2, S3, S4 and HCC, respectively; there were differences among groups HCC and S1 or S2; S4, S3 or S2 and S1 (P<0.05), statistically.

CONCLUSION

The length and thickness of spleen and width of splenic vein were increased as the deterioration of severity of hepatic fibrosis. The length of spleen is more sensitive in indicating the severity of liver fibrosis. Both AFP level and splenic size were elevated as the increase rate of spontaneous conversion from HBeAg to anti-HBe. The risk of hepatocellular carcinoma associated with hepatitis B exists in any stages of liver fibrosis.

Long-term outcomes of thymosin-alpha 1 and interferon alpha-2b combination therapy in patients with hepatitis B e antigen (HBeAg) negative chronic hepatitis B

Hepatitis B e antibody (HbeAb) and hepatitis B virus (HBV) DNA positive chronic hepatitis is a clinical entity, distinct from classical hepatitis B e antigen (HbeAg) positive chronic hepatitis B. Our aim was to evaluate the long-term therapeutic efficacy of the combination of interferon alpha-2b and thymosin-alpha1 compared with lamivudine plus interferon alpha-2b and interferon alpha-2b alone. Fifty-two patients with HbeAg-negative chronic hepatitis B were assigned to three different groups in a nonrandomized manner. Group 1 (n = 27) received thymosin-alpha1 [1.6 mg subcutaneously (sc), twice a week] and interferon alpha-2b (10 MIU sc, three times per week) for 26 weeks, subsequently followed by interferon alpha-2b monotherapy at the same dosage for an additional 26 weeks. Group 2 (n = 10) received interferon alpha-2b (10 MIU sc, three times per week) for 52 weeks. Group 3 (n = 15) received interferon alpha-2b (10 MIU sc, three times per week) and lamivudine [100 mg orally (po), q.d.] for 52 weeks, followed by continuous lamivudine (100 mg po, q.d.) therapy. By the end of 78 weeks, a sustained response (SR-6 mo) was seen in 74% (20/27) of the patients within Group 1. On the contrary, Groups 2 and 3 had sustained response rates of 40 (4/10) and 53.3% (8/15), respectively (p = 0.13). At the end of 12 months post-treatment in Group 1, a virological and biochemical response rate was seen in 70.3% of patients (19/27); in contrast, Groups 2 and 3 had response rates of 20 (2/10) and 26.6% (4/15), respectively (p = 0036). At the end of the 18-month post-treatment follow-up period, 71.4% (19/27) of patients in Group 1, 10% of patients in Group 2 (1/10), and 20% of patients in Group 3(3/15) preserved their sustained response (p = 0.0003). Interferon alpha-2b and thymosin-alpha1 combination therapy results in significant virological and biochemical response rates compared with standard therapeutic regimens and is well tolerated.

Effect of thymosin-α1 on immune function with chronic hepatitis B

AIM

To realize effect of thymosin-α1 (Tα1) on immune function with chronic hepatitis B (CHB) and to evaluate the efficacy of Tα1 in the treatment of CHB.

METHODS

Sixty patients with CHB were randomly chosen. Twenty-five cases were received Tα1 (1.6 mg, sc, twice a week, 3-6mo) and thirty-five were received Tα1 combined with Lamivudine (0.1 g, po, once a day, 3-6 mo). Hepatic function, virological analyses (HBeAg, HBsAg, HBV-DNA) and immunological analyses (periperal blood T lymphocytes subset, IFN-α and IL-4 levels) from patients in pretreatment and posttreatment were observed.

RESULTS

At the end of treatment, ALT and T-Bil were decreased in the group of Tα1 combined with Lamivudine (P<0.01), HBeAg/HBsAg remained negative (n = 9) and HBV-DNA levels were also low (n = 14) in the group of Tα1 combined with Lamivudine (P<0.01 and P<0.05, respectively) as compared with healthy individuals. CD₄⁺ T Cell (from 31.3±2.4 to 36.1±2.5), the level of IFN-α(from 71.3±21.0 to 83.7±21.4) and Th1/Th2 (from 0.79±0.2 to 0.98±0.3) increased in the group of Tα1 (P<0.01, P<0.05 and P<0.05, respectively).

CONCLUSION

Tα1 is efficient to treat patients with CHB because it can elevate the level of cellular immunity, which is beneficial to viral clearance.

A novel HBV antisense RNA gene delivery system targeting hepatocellular carcinoma

AIM

To construct a novel HBV antisense RNA delivery system targeting hapatocellular carcinoma and study its inhibitory effect in vitro and in vivo.

METHODS

GE7,a 16-peptide specific to EGFR, and HA20,a homologue of N-terminus of haemagglutinin of influenza viral envelope protein, were synthesized and conjugated with polylysin. The above conjugates were organized into the pEBAF-as-preS2, a hepatocarcinoma specific HBV antisense expression vector, to construct a novel HBV antisense RNA delivery system, named AFP-enhancing 4-element complex. Hepatocelluar carcinoma HepG2.2.15 cells was used to assay the in vitro inhibition of the complex on HBV. Expression of HBV antigen was assayed by ELISA. BALB/c nude mice bearing HepG2.2.15 cells were injected with AFP-enhancing 4-element complex. The expression of HBV antisense RNA was examined by RT-PCR and the size of tumor in nude mice were measured.

RESULTS

The AFP-enhancing 4-element complex was constructed and DNA was completely trapped at the slot with no DNA migration when the ratio of polypeptide to plasmid was 1:1. The expression of HBsAg and HBeAg of HepG2.2.15 cells was greatly decreased after being transfected by AFP-enhancing 4-element complex. The inhibitory rates were 33.4 % and 58.5 % respectively. RT-PCR showed HBV antisense RNA expressed specifically in liver tumor cells of tumor-bearing nude mice. After 4 injections of AFP-enhancing 4-element complex containing 0.2 micro g DNA, the diameter of the tumor was 0.995 cm+/-0.35, which was significantly smaller than that of the control groups(2.215 cm+/-0.25, P<0.05).

CONCLUSION

AFP-enhancing 4-element complex could deliver HBV antisense RNA targeting on hepatocarcinoma and inhibit both HBV and liver tumor cells in vitro and in vivo.

Effect of ribozymes on inhibiting expression of HBV mRNA in HepG2 cells

AIM: To study the activity of ribozymes with multiple cleavage sites and mutated ribozymes on expression of HBV mRNA in HepG2 cells.

METHODS: The triple ribozymes and two cis-ribozymes or two mutated ribozymes were inserted, respectively, into five kinds of eukaryotic plasmids, which were cotransfected into the HepG2 cells with p1.2Ⅱplasmid carring genome of adv-subtype HBV. Cleavage effect of ribozymes on HBeAg and HBcAg were detected by ELISA and laser confocal imaging technique.

RESULTS: The transfected HepG2 cells expressed the expected ribozyme and muta-ribozyme. Intracellular level of HBeAg was surpressed variably with variety of ribozymes. The ribozyme plasmid with tRNA promoter demonstrated the highest inhibitory rate at 81% for suppression HBeAg expression.

CONCLUSION: The ribozymes exert varied inhibitory effect on the expression of HBV in HepG2 cells depending on kinds of eukaryotic expressing plasmids.

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Changes in serum and histology of patients with chronic hepatitis B after interferon alpha-2b treatment

AIM: Chronic hepatitis B is a serious health problem. Interferon has long been used to treat Chronic hepatitis B. To evaluate the effects of interferon on chronic hepatitis B better, we designed the study to investigate the changes in sera and liver histology of patients with chronic hepatitis B after interferon alpha-2b treatment.

METHODS: Twenty-four patients with chronic hepatitis B were enrolled in this study. They all received interferon alpha-2b treatment as following: 3 million units, i.m. t.i.w., for 18 weeks. Sera of all patients were obtained respectively for evaluation of ALT, HBsAg, HBcAg, HBeAg, HBV DNA and TIMP-1 before and after interferon treatment, also a liver biopsy pre- and post-treatment was performed for comparison of HAI, HBsAg, HBcAg, HBeAg, TIMP-1 and activated HSC in the liver tissue.

RESULTS: Patients who had normalization of serum ALT and seroconversion of HBeAg and/or HBV DNA (blot hybridization) after treatment were defined as responders. The response rate in this study group was 37.5% (7/24). Compared to pretreatment, the serum HBV DNA and TIMP-1 decreased significantly (P < 0.05), so did the HAI, HBcAg, HBeAg, TIMP-1 and activated HSC (P < 0.05).

CONCLUSION: The significant decrease in HBV DNA in sera, the seroconversion of HBeAg, and the decrease of viral expression in liver indicated that interferon alpha-2b treatment can inhibit viral replication. The normalization of ALT in sera and the improvement of HAI in liver showed that interferon alpha-2b can improve the liver histology of patients with chronic hepatitis B. At the same time, interferon alpha-2b treatment can reduce the TIMP-1 in serum and liver and decrease the number of activated HSC, which may allievate or inhibit hepatic fibrosis. Although the response rate was unsatisfactory, interferon play a benefical role on patients with chronic hepatitis B in other respects. We still need further studies to improve the therapy effects.

Hepatoprotective role of ganoderma lucidum polysaccharide against BCG-induced immune liver injury in mice

AIM: To examine the effect of ganoderma lucidum polysaccharide (GLP) on the immune liver injury induced by BCG infection, and investigate the relationship between degrees of hepatic damage and NO production in mice.

METHODS: Immune hepatic injury was markedly induced by BCG-pretreatment (125 mg·kg^-1, 2-week, iv) or by BCG-pretreatment plus lipopolysaccharide (LPS, 125 μg·kg^-1, 12-hour, iv) in mice in vivo. Hepatocellular damage induced by BCG-pretreated plus inflammatory cytokines mixture (CM), which was included TNF-α, IL-1β, IFN-γ and LPS in culture medium in vitro. Administration of GLP was performed by oral or incubating with culture medium at immune stimuli simultaneity. Liver damage was determined by activity of alanine aminotransferase (ALT) in serum and in hepatocytes cultured supernatant, by liver weight changes and histopathological examination. NO production in the cultured supernatant was determined by the Griess reaction. Moreover, inducible nitric oxide synthase (iNOS) protein expression was also examinated by immunohistochemical method.

RESULTS: Immune hepatic injury was markedly induced by BCG or BCG plus inflammatory cytokines in BALB/c mice in vivo and in vitro. Under BCG-stimulated condition, augment of the liver weight and increase of the serum/supernatant ALT level were observed, as well as granuloma forming and inflammatory cells soakage were observed by microscopic analysis within liver tissues. Moreover, NO production was also increased by BCG or/and CM stimuli in the culture supernatant, and a lot of iNOS positive staining was observed in BCG-prestimulated hepatic sections. Application of GLP significantly mitigated hepatic tumefaction, decreased ALT enzyme release and NO production in serum/supernatant, improved the pathological changes of chronic and acute inflammation induced by BCG-stimuli in mice. Moreover, the immunohistochemical result showed that GLP inhibited iNOS protein expression in BCG-immune hepatic damage model.

CONCLUSION: The present study indicates that NO participates in immune liver injury induced by Mycobacterium bovis BCG infection. The mechanisms of protective roles by GLP for BCG-induced immune liver injury may be due to influence NO production in mice.

Construction and characterization of an experimental ISCOMS-based hepatitis B polypeptide vaccine

AIM: To characterize the biochemical and immunological properties of an experimental ISCOMS vaccine prepared from a novel therapeutic polypeptide based on T cell epitopes of HBsAg, and a heptatis B-ISCOMS was prepared and investigated.

METHODS: An immunostimulating complexes (ISCOMS)-based vaccine containing a novel therapeutic hepatits B polypeptide was prepared by dialysis method, and its formation was visualized by electron microscopy and biochemically verified by SDS-polyacrylamide gel electrophoresis. Amount of the peptide within ISCOMS was determined by Bradford assay, and specific CTL response was detected by ELISPOT assay.

RESULTS: Typical cage-like structures of submicroparticle with a diameter of about 40 nm were observed by electron microscopy. Results from Bradford assay showed that the level of peptide incorporation was about 0.33 g•L⁻¹. At the paralleled position close to the sixth band of the molecular weight marker (3480 kDa) a clear band was shown in SDS-PAGE analysis, indicating successful incorporation of polypeptide into ISCOMS. It is suggested that ISCOMS delivery system could efficiently improve the immunogenicity of polypeptide and elicit specific immune responses in vivo by the results of ELISPOT assay, which showed that IFN-γ producing cells (specific CTL responses) were increased (spots of ISCOMS-treated group: 47 ± 5, n = 3; control group: 5 ± 2, n = 3).

CONCLUSION: ISCOMS-based hepatitis B polypeptide vaccine is successfully constructed and it induces a higher CTL response compared with short polypeptides vaccine in vivo.

Anti-HBV hairpin ribozyme-mediated cleavage of target RNA in vitro

AIM: To study the preparation and cleavage activity of HpRz directed against the transcript of HBV core gene in vitro.

METHODS: HpRz gene designed by computer targeting the transcript of HBV core gene was cloned into the vector p1.5 between 5’-cis-Rz and 3’-cis-Rz. ³²p-labeled HpRz transcript proved whether the vector fit for the preparation of hairpin ribozyme in vitro. ³²p-labeled pKC transcript containing HBV core region as target-RNA was transcribed using T₇ RNA polymerase and purified by denaturing PAGE. Cold HpRz transcript was incubated with ³²p-labeled target-RNAs under different conditions and radio autographed after denaturing polyacrylamide gel electrophoresis.

RESULTS: HpRz has the specific ability of cleavage of target RNA at 37 °C and 12 mM MgCl₂. K_m = 26.31 nmol/L, K_cat = 0.18/min. These results revealed that the design of HpRz was correct.

CONCLUSION: HpRz prepared in this study possesses specific catalytic activity from the identification of cleavage activity. These results indicate that hairpin ribozyme may intracellularly inhibit the replication of HBV, therefore it may become a novel potent weapon for the treatment of hepatitis B.