Role of Antivirus Therapy in Treatment of Hepatocellular Carcinoma with Chronic Hepatitis B Infection

Objective： To observe the recurrence and prognosis of hepatocellular carcinoma （HCC） patients coexisting with chronic hepatitis B infection with active virus replication after receiving antivirus therapy using lamivudine and thymosin α1 （Tα1） postoperatively. Methods： From Jan. 2000 to Dec. 2003, 70 patients with HCC coexisting chronic hepatitis B infection with active virus replication were prospectively divided into two groups： control group （n=35） received hepatectomy only; treatment group （n=35） received hepatectomy and lamivudine plus Tα1 therapy postoperatively. The suppression of HBV-DNA, HBeAg seroconverted rate, tumor recurrent rate and the median survival for the two groups were observed and calculated. Results： In treatment group and control group, the 2-year HBV-DNA suppression rate was 100% vs. 4% （P=0.0000）; HBeAg seroconverted rate was 73.0% vs. 7.5% （P〈0.05）; the recurrent rate was 10.0 vs 6.5 months （P=0.0032）; the median survival time was 12.5 vs. 6.0 months （P=0.0023）, respectively. Conclusion： Antivirus therapy using lamivudine and Tα1 postoperatively may suppress the HBV reaction, delay the recurrent time and prolong the survival for HCC patients coexisting chronic HBV infection with active virus replication.

Detection of apoptosis induced by new type gosling viral enteritis virus in vitro through fluorescein annexin V-FITC/PI double labeling

AIM: To achieve a better understanding of the pathogenesis of new type gosling viral enteritis virus (NGVEV) and the relationship between NGVEV and host cells. METHODS: The apoptosis of duck embryo fibroblasts (DEF) induced by NGVEV was investigated by fluorescence-activated cell sorter (FACS) and fluorescence microscope after the cells were stained with Annexin V-FITC and propidium iodide (PI). RESULTS: By staining cells with a combination of fluorescein annexin V-FITC and PI, it is possible to distinguish and quantitatively analyze non-apoptotic cells (Annexin V-FITC negative/PI negative), early apoptotic cells (Annexin V-FITC positive/PI negative), late apoptotic/necrotic cells (Annexin V-FITC positive/ PI positive) and dead cells (Annexin V-FITC negative/PI positive) through flow cytometry and fluorescence microscope. The percentage of apoptotic cells increased with the incubation time and reached a maximum at 120 h after infection, while the percentage of non- apoptotic cells decreased.

Factors predicting occurrence and prognosis of hepatitis-B-virus-related hepatocellular carcinoma

Primary liver cancer is an important cause of cancer death, and hepatocellular carcinoma （HCC） accounts for 70%-85% of total liver cancer worldwide. Chronic hepatitis B virus （HBV） infection contributes to 〉 75% of HCC cases. High serum viral load is the most reliable indicator of viral replication in predicting development of HCC. HBV genotype C is closely associated with HCC in cirrhotic patients aged 〉 50 years, whereas genotype B is associated with development of HCC in non-cirrhotic young patients and postoperative relapse of HCC. Different HBV subgenotypes have distinct patterns of mutations, which are clearly associated with increased risk of HCC. Mutations accumulate during chronic HBV infection and predict occurrence of HCC. Chronic inflammation leads to increased frequency of viral mutation via cellular cytidine deaminase induction. Mutations are negatively selected by host immunity, whereas some immuno-escaped HBV mutants are active in hepatocarcinogenesis. Inflammatory pathways contribute to the inflammation-necrosis-regeneration process, ultimately HCC. Their hallmark molecules can predict malignancy in HBV-infected subjects. Continuing inflammation is involved in hepatocarcinogenesis and closely related to recurrence and metastasis. HBV load, genotype C, viral mutations and expression of inflammatory molecules in HBV-related HCC tissues are significantly associated with poor prognosis. Imbalance between intratumoral CD8^＋T cells and regulatory T cells or Thl and Th2 cytokines in peritumoral tissues can predict prognosis of HBV-related HCC. These factors are important for developing active prevention and surveillance of HBV-infected subjects who are more likely to develop HCC, or for tailoring suitable treatment to improve survival or postpone postoperative recurrence of HCC.

Enhancement of CTLs induced by DCs loaded with ubiquitinated hepatitis B virus core antigen

AIM： To investigate whether hepatitis B virus （HBV） could induce a hepatitis B virus core antigen （HBcAg）specific cytotoxic T lymphocyte （CTL） response in vitro by dendritic cells （DCs） transduced with lentiviral vector-encoding ubiquitinated hepatitis B virus core antigen （LV-Ub-HBcAg）.METHODS： Recombinant LV-Ub-HBcAg were transfected into highly susceptible 293 T cells to obtain high virus titres, Bone marrow-derived DCs isolated from BALB/c mice were cultured with recombinant granulocyte-macrophage colony-stimulating factor and recombinant interleukin （IL）-4. LV-Ub-HBcAg, lentiviral vector-encoding hepatitis B virus core antigen （LV-HBcAg）, lentiviral vector （LV） or lipopolysaccharide were added to induce DC maturation, and the DC phenotypes were analyzed by flow cytometry. The level of IL-12 in the supernatant was detected by enzyme-linked immunosorbent assay （ELISA）. T lymphocytes were proliferated using Cell Counting Kit-8. DCs were cultured and induced to mature using different LVs, and co-cultured with allogeneic T cells to detect the secretion levels of IL-2, IL-4, IL-10and interferon-γ in the supernatants of T cells by ELISA. Intracellular cytokines of proliferative T cells were analyzed by flow cytometry, and specific CTL activity was measured by a lactate dehydrogenase release assay.RESULTS： LV-Ub-HBcAg-induced DCs secreted more IL-12 and upregulated the expression of CD80, CD86 and major histocompatibility class ]I, DCs sensitised by different LVs effectively promoted cytokine secretion; the levels of IL-2 and interferon-y induced by LV-Ub- HBcAg were higher than those induced by LV-HBcAg, Compared with LV-HBcAg-transduced DCs, LV-Ub- HBcAg-transduced DCs more efficiently stimulated the proliferation of T lymphocytes and generated HBcAgspecific cytotoxic T lymphocytes.CONCLUSION： LV-Ub-HBcAg effectively induced DC maturation. The mature DCs efficiently induced T cell polarisation to Thl and generated HBcAg-specific CTLs.

Mechanism of T cell hyporesponsiveness to HBcAg is associated with regulatory T cells in chronic hepatitis B

AIM： To study the mechanisms of hyporesponsiveness of HBV-specific CD4^＋ T cells by testing TH1 and TH2 commitment and regulatory T cells. METHODS： Nine patients with chronic hepatitis B were enrolled. Peripheral blood mononuclear cells were stimulated with HBcAg or HBsAg to evaluate their potential to commit to TH1 and TH2 differentiation. HBcAg-specific activity of regulatory T cells was evaluated by staining with antibodies to CD4, CD25, CTLA-4 and interleukin-10. The role of regulatory T cells was further assessed by treatment with anti-interleukin-10 antibody and depletion of CD4^＋CD25^＋ cells. RESULTS： Level of mRNAs for T-bet, IL-12R β2 and IL-4 was significantly lower in the patients than in healthy subjects with HBcAg stimulation. Although populations of CD4^＋CD25^highCTLA-4^＋ T cells were not different between the patients and healthy subjects, IL-10 secreting cells were found in CD4^＋ cells and CD4^＋CD25^＋ cells in the patients in response to HBcAg, and they were not found in cells which were stimulated with HBsAg. Addition of anti-IL-10 antibody recovered the amount of HBcAgspecific TH1 antibody compared with control antibody （P 〈 0.01, 0.34% ± 0.12% vs 0.15% ± 0.04%）. Deletion of CD4^＋CD25^＋ T cells increased the amount of HBcAgspecific TH1 antibody when compared with lymphoo/tes reconstituted using regulatory T cells （P 〈 0.01, 0.03% ± 0.02% vs 0.18% ± 0.05%）.CONCLUSION： The results indicate that the mechanism of T cell hyporesponsiveness to HBcAg includes activation of HBcAg-induced regulatory T cells in contrast to an increase in TH2-committed cells in response to HBsAg.

Expression of β-catenin in hepatocellular carcinoma

AIM: The beta-catenin has been recognized as a critical member of the Wnt signaling pathway and plays an important role in the generation/differentiation of many tissues. Inappropriate activation of this pathway has been implicated in carcinogenesis. The mechanism underlying the development as well as its prognosis of hepatocellular carcinoma (HCC) has remained unclear. The purpose of this study is to analyze the expression of beta-catenin in HCC in relation to histological grades and viral hepatitis backgrounds. METHODS: Thirty-two sections were selected at random from autopsy and surgical cases of HCC. Immuohistologically, the location and positivity of beta-catenin expression in HCC was examined. RESULTS: Normal hepatocytes did not express beta-catenin. In 78% of HCC beta-catenin was expressed at the membrane of the cells, with or without cytoplasmic and/or nuclear expression. The tumor cells with well-and moderately-differentiated grades expressed frequently at the membrane and cytoplasm compared with poorly-differentiated type. Nuclear expression of beta-catenin was prone to occur in the tumor cells of poorly-differentiated grade. There were 15% of hepatitis C virus (HCV) backgrounds with nuclear expression. In contrast, there was 38% with nuclear expression in hepatitis B virus (HBV) backgrounds. In nonB-nonC hepatitis, no case expressed nuclear beta-catenin. CONCLUSION: The beta-catenin expression in HCC cells was heterogenous among types of hepatitis viral infection. Wnt signaling pathway might be deeply involved in less-differentiated HCC and HBV background. (C) 2005 The WJG Press and Elsevier Inc. All rights reserved.

Response of porcine hepatocytes in primary culture to plasma from severe viral hepatitis patients

AIM： To observe the effects of plasma from patients with severe viral hepatitis （SVHP） on the growth and metabolism of porcine hepatocytes and the clinical efficiency of bioartificial liver device.METHODS： Hepatocytes were isolated from male porcines by collagenase perfusion. The synthesis of DNA and total protein, leakages of AST and LDH, changes in glutathione （GSH）, catalase and morphology of porcine hepatocytes exposed to SVHP were investigated to indicate the effect of plasma from patients with severe hepatitis on the growth, injury, detoxification, and morphology of porcine hepatocytes.RESULTS： The synthesis of DNA and protein was inhibited in the medium containing 100% SVHP compared to the controls. The leakages of LDH and AST increased in porcine hepatocytes following exposure to 100% SVHP for 5 h. The difference between 100% SVHP and 10% newborn calf serum （NCS） was significant in t-test （LDH： t = 24.552, P = 0.001; AST： t = 4.169, P = 0.014）. After exposure to SVHP for 24 h, alterations in GSH status were significant （F = 2.746, P〈0.05） between porcine hepatocytes in 100% SVHP and 10% NCS, but no alteration occurred in the culture medium after 48 h （F = 4.378, ,P〈0.05）. A similar profile was observed in catalase activity. Many round vacuoles were observed in porcine hepatocytes cultured in SVHR The membranes of these cells became indistinct and almost all the cells died on d 5.CONCLUSION： Plasma from patients with severe hepatitis inhibits the growth, injures membrane, disturbs GSH homeostasis and induces morphological changes of porcine hepatocytes, It is suggested that SVHP should be pretreated to reduce the toxin load and improve the performance of porcine hepatocytes in extracorporeal liver-support devices.

Polymorphisms of some cytokines and chronic hepatitis B and C virus infection

AIM： To study the relationship between the polymorphisms in some cytokines and the outcome of hepatitis B virus （HBV） and hepatitis C virus （HCV） infection. METHODS： Samples were obtained from 203 patients infected with HBV and/or HCV while donating plasma in 1987, and 74 controls were obtained from a rural area of North China. Antibodies to HBV or HCV antigens were detected by enzyme-linked imrnunoassay. The presence of viral particles in the serum was determined by nested reverse-transcriptase polymerase chain reaction （PCR）. Hepatocellular injury, as revealed by alanine aminotransferase （ALT） and aspartate aminotransferase level, was detected by a Beckman LX-20 analyzer. DNA was extracted from blood cells. Then, the single nucleotide polymorphisms of IL-2-330, IFN-γ＋874, IL-10-1082/-592 and IL-4-589 were investigated by restriction fragment length polymorphism-PCR or sequence specific primer-PCR.RESULTS： Persistent infection with HBV, HCV, and HBV/HCV coinfection was associated with IL-2-330 TT genotype and T allele, IFN-γ＋874 AA genotype, and IL-10-1082 AA genotype. The clinical outcome of HBV and/or HCV infection was associated with IL-2-330 TT genotype and T allele, IFN-γ＋874 AA genotype, and IL-10-1082 AA genotype. IL-2-330 GG genotype frequency showed a negative correlation with clinical progression, IL-10-1082 AA genotype frequency showed a positive correlation and IL-10-1082 AG genotype frequency showed a negative correlation with clinical progression. HCV RNA positive expression was associated with IL-10-1082 AA genotype and the A allele frequency. Abnormal serum ALT level was associated with IL-10-592 AC genotype frequency and IL-4-589 CC genotype, CT genotype, and the C allele. CONCLUSION： These results suggest that polymorphisms in some cytokine genes influence persistent HBV and HCV infection, clinical outcome, HCV replication, and liver damage.

Refractory ulcerative colitis accompanied with cytomegalovirus colitis and multiple liver abscesses: A case report

Various hepato-biliary complications are an increased incidence in patients with inflammatory bowel disease,and portal bacteremia is well documented in patients with ulcerative colitis (UC). However, few reports mention UC in association with liver abscesses. Recently, there are several reports describing cytomegalovirus (CMV) infection in association with disease exacerbation and steroid refractoriness in patients with UC. Here we present a case of refractory UC accompanied with multiple liver abscesses and CMV colitis. The patient, a 72-year-old male, with a five-year history of repeated admissions to our hospital for UC, presented with an exacerbation of his UC.Sigmoidoscopy performed on admission suggested that his UC was exacerbated, then he was given prednisolone and mesalazine orally, and betamethasone enemas.However, he had exacerbated symptoms. Repeat sigmoidoscopy revealed multiple longitudinal ulcers and pseudopolyps in the rectosigmoid colon. Although immunohistochemical staining of biopsy specimens and the serum testing for antigenemia were negative on admission and after the repeat sigmoidoscopy, they became histologically positive for CMV. Nonetheless, the patient developed spiking fevers, soon after ganciclovir was administered. Laboratory studies revealed an increased white cell count with left shift, and Enterococcus fecalis grew in blood cultures. An abdominal computed tomography (CT) scan was obtained and the diagnosis of liver abscesses associated with UC was made, based on CT results. The hepatic abscesses were successfully treated with intravenous meropenem for 6 wk, without further percutaneous drainage. To our knowledge, this is the first reported case of multiple liver abscesses that develop during UC exacerbation complicated by CMV colitis.

Eosinophilic gastroenteritis with cytomegalovirus infection in an immunocompetent child

A 3-year-old boy developed transient protein-losing gastroenteropathy associated with cytomegalovirus (CMV) infection. Both IgG and IgM antibodies to CMV were positive in a serologic blood test. Upper gastrointestinal endoscopy showed multiple erosions throughout the body of the stomach, without enlarged gastric folds. Histological examination of the biopsy specimens indicated eosinophilic gastroenteritis and CMV infection. The patient had complete resolution without specific therapy for CMV in four weeks. An allergic reaction as well as CMV infection played important roles in the pathogenesis of this case.

Hepatitis C virus infection and health-related quality of life

Hepatitis C virus(HCV) hepatitis and other diseases related to HCV,such as cryoglobulinemia,lymphoma and renal failure,impair health-related quality of life(HRQoL).In addition,HCV per se might directly influence HRQoL via colonization of microglia in the brain or,indirectly,via the effect of systemic inflammatory cytokines which,in turn,can trigger brain interleukin production.The treatment of HCV-related disorders with interferon(IFN) has an effect on HRQoL.Initially,IFN causes a transient deterioration of HRQoL,due to the induction of depression and other side effects of treatment.Subsequently,the subjects who obtain a sustained virologic response experience an improvement in HRQoL.Only rarely does interferon treatment causes permanent detrimental effects on HRQoL,due to residual psychiatric or neurologic side effects.Liver transplantation is the only treatment for end-stage HCV-related liver disease.HRQoL generally improves massively a few months after transplantation,except in the case of serious complications of the transplant procedure.Furthermore,high levels of anxiety and neuroticism pre-transplant are associated with lower HRQoL one year after transplant.Additionally,six months after transplant,patients with HCV who experience virologic recurrence show significantly greater depression,anxiety,phobic anxiety,and paranoid ideation than anti-HCV-negative patients.In conclusion,optimal care for the overall well-being of patients with HCV infection requires adequate knowledge of their neurological and psychological status.

Natural history of cytomegalovirus infection in a series of patients diagnosed with moderate-severe ulcerative colitis

AIM： To evaluate the natural history of human cytomegalovirus （HCMV） infection in a series of 28 ulcerative colitis patients in whom the search for HCMV was positive. METHODS： A series of 85 patients with moderate-se- vere ulcerative colitis flare-up were evaluated for a HCMV search by performing a haematoxylin and eosin stain, immunohistochemical assay and nested polymerase chain reaction on rectal biopsies. Among 85 screened patients （19 of whom were steroid resistant/dependant）, 28 were positive for HCMV; after remission the patients were followed up clinically and histologically. RESULTS： Among the 22 patients with complete follow- up, in 8 （36%） patients HCMV-DNA persisted in the in- testinal specimens. Among the HCMV positive patients, 4 （50%） experienced at least one moderate-severeflare-up of colitis without evidence of peripheral HCMV. Among the 14 HCHV negative patients, 3 with pouches developed pouchiUs and 5 out of 11 （45%） experienced a colitis flare-up. CONCLUSION： Our preliminary results suggest that HCHV may remain in the colon afber an acute coltis flare- up despite remission; it seems that the virus is not responsible for the disease relapse.

Cytomegalovirus enteritis mimicking Crohn's disease in a lupus nephritis patient:A case report

Cytomegalovirus(CMV)infection of the gastrointestinal (GI)tract has been reported in both immunocompetent and,more frequently,in immunocompromised patients.We describe a case of a 19-year-old male who developed CMV infection of the terminal ileum while receiving immunosuppression for lupus nephritis. This was a distinctly unusual site of infection which clinically mimicked Crohn's ileitis.We note that reports of terminal ileal CMV infection have been infrequent. Despite a complicated hospital course,ganciclovir therapy was effective in resolving his symptoms and normalizing his ileal mucosa.This report highlights the importance of accurate histological diagnosis and clinical follow-up of lupus patients with GI symptoms undergoing intense immunosuppression.

No association of the cytotoxic T-lymphocyte associated gene CTLA4 +49A/G polymorphisms with Crohn's disease and ulcerative colitis in Hungarian population samples

AIM： The goal of the current work was to analyse the prevalence of the ＋49A/G variant of the cytotoxic T-lymphocyte antigen 4 gene （CTLA4） in Hungarian patients with Crohn＇s disease （CD） and ulcerative colitis （UC）. METHODS： A total of 130 unrelated subjects with CD and 150 with UC, and 170 matched controls were genotyped for the single nucleotide polymorphism （SNP）. The genotypes were determined by using PCR/RFLP test. RESULTS： The G allele frequency and the prevalence of the GG genotype were 38.1% and 12.3% in the CD group, 40.6% and 18.6% in the UC patients, and 37.4% and 15.9% in the control group, respectively. CONCLUSION： The results of the current study show that carriage of the ＋49G SNP in heterozygous or in homozygous form does not confer risk either for CD or for UC in the Hungarian population.

Ion Channels as Antivirus Targets

Ion channels are membrane proteins that are found in a number of viruses and which are of crucial physiological importance in the viral life cycle. They have one common feature in that their action mode involves a change of electrochemical or proton gradient across the bilayer lipid membrane which modulates viral or cellular activity. We will discuss a group of viral channel proteins that belong to the viroproin family, and which participate in a number of viral functions including promoting the release of viral particles from cells. Blocking these channel-forming proteins may be ＂lethal＂, which can be a suitable and potential therapeutic strategy. In this review we discuss seven ion channels of viruses which can lead serious infections in human beings： M2 of influenza A, NB and BM2 of influenza B, CM2 of influenza C, Vpu of HIV-1, p7 of HCV and 2B of picomaviruses.

A low prevalence of H pylori and endoscopic findings in HIV-positive Chinese patients with gastrointestinal symptoms

AIM： To compare the prevalence of H pylori infection, peptic ulcer, cytomegalovirus （CNV） infection and Candida esophagitis in human immunodeficiency virus （HIV）- positive and HIV-negative patients, and evaluate the impact of CD4 lymphocyte on H pylori and opportunistic infections. METHODS： A total of 151 patients （122 HIV-positive and 29 HIV-negative） with gastrointestinal symptoms were examined by upper endoscopy and biopsy. Samples were assessed to determine the prevalence of Hpylori infection, CMV, candida esophagitis and histologic chronic gastritis. RESULTS： The prevalence of Hpylori was less common in HIV-positive patients （22.1%） than in HIV-negative controls （44.8%; P 〈 0.05）, and the prevalence of H pylori displayed a direct correlation with CD4 count stratification in HIV-positive patients. In comparison with HIV-negative group, HIV-positive patients had a lower incidence of peptic ulcer （20.7% vs 4.1%; P 〈 0.01）, but a higher prevalence of chronic atrophy gastritis （6.9% vs 24.6%; P 〈 0.05）, Candida esophagitis and CMV infection. Unlike HIV-negative group, H pylori infection had a close relationship to chronic active gastritis （P 〈 0.05）. In HIV-positive patients, chronic active gastritis was not significantly different between those with Hpylori infection and those without. CONCLUSION： The lower prevalence of H pylori infection and peptic ulcer in HIV-positive patients with gastrointestinal symptoms suggests a different mechanism of peptic ulcerogenesis and a different role of H pylori infection in chronic active gastritis and peptic ulcer. The pathogen of chronic active gastritis in HIV-positive patients may be different from the general population that is closely related to Hpylori infection.

Molecular Characterization of China Human Rabies Vaccine Strains

To understand the molecular characteristics of China human rabies vaccine strains, we report the full-length genome of the aG strain and present a comprehensive analysis of this strain and almost all available lyssavirus genomes （58 strains） from GenBank （as of Jan 6, 2011）. It is generally considered that the G protein plays a predominant role in determining the pathogenicity of the virus, to this end we predicted the tertiary structure of the G protein of aG strain, CTN 181 strain and wild type strain HN 10 based on the crystal structure of Vesicular stomatitis virus （VSV） G. The predicted RABV G structure has a similar topology to VSV G and the ectodomain can be divided into 4 distinct domains DI - DIV. By mapping the characterized mutations to this structure between China vaccine strains and their close street strains, we speculate that the G303（P-H） mutations of CTN181 and HN10 causing D II 3D change may be associated with the attenuated virulence in both strains. Specifically, the two signature mutations （G165P and G231P） in the aG strain are withinβsheets, suggesting that both sites are of structural importance.

Conserved balance of hepatocyte nuclear DNA content in mononuclear and binuclear hepatocyte populations during the course of chronic viral hepatitis

AIM： TO analyze the percentages of hepatocytes with increased nuclear DNA content, i.e., tetraploid （4n） and octoploid （Sn） nuclei, and then compared mononuclear and binuclear hepatocyte populations： METHODS： The percentages of mononuclear diploid （2n）, 4n, and 8n hepatocytes and those of binuclear 2 × 2n, 2 × 4n, and 2 × 8n hepatocytes were determined with a method that can simultaneously measure hepatocyte nuclear DNA content and binuclearity in 62 patients with chronic hepatitis B or C. The percentage of 4n and 8n hepatocytes in the mononuclear hepatocyte population was compared with the percentage of 2 × 4n and 2 × 8n hepatocytes in the binuclear hepatocyte population. RESULTS： The percentages of 4n and 8n hepatocytes in mononuclear hepatocytes and 2 ×4n and 2 × 8n hepatocytes in binuclear hepatocytes were similar, regardless of the activity or fibrosis grade of chronic hepatitis and regardless of the infecting virus. CONCLUSION： The distribution of nuclear DNA content within mononuclear and binuclear hepatocyte populations was conserved during the course of chronic viral hepatitis.

Development of HBsAg-Binding Aptamers that bind HepG2.2.15 cells via HBV surface antigen

Hepatitis B virus surface antigen （HBsAg）, a specific antigen on the membrane of Hepatitis B virus （HBV）-infected cells, provides a perfect target for therapeutic drugs. The development of reagents with high affinity and specificity to the HBsAg is of great significance to the early-stage diagnosis and treatment of HBV infection. Herein, we report the selection of RNA aptamers that can specifically bind to HBsAg protein and HBsAg-positive hepatocytes. One high affinity aptamer, HBs-A22, was isolated from an initial 115 met library of -1.1 ×10^15 random-sequence RNA molecules using the SELEX procedure. The selected aptamer HBs-A22 bound specifically to hepatoma cell line HepG2.2.15 that expresses HBsAg but did not bind to HBsAg-devoid HepG2 cells. This is the first reported RNA aptamer which could bind to a HBV specific antigen. This newly isolated aptamer could be modified to deliver imaging, diagnostic, and therapeutic agents targeted at HBV-infected cells.