Production and efficacy of a dendritic cell-based therapeutic vaccine for murine chronic hepatitis B virus carrierer

Recently a new field of immunological research and clinical application of vaccines for therapeutic purposes (vaccine therapy) has been developed for treating several chronic viral infections including chronic hepatitis B virus (HBV) infection. Administration of vaccine containing hepatitis B surface antigen (HBsAg) for 1 year has resulted in negative HBsAg and development of antibody to HBsAg (anti-HBs) in some, but not in all, HBV transgenic mouse (HBV-Tg). In order to develop more potent regimen of vaccine therapy for chronic HBV carrier, we prepared a dendritic cell (DC)-based therapeutic vaccine and evaluated their therapeutic potential in HBV-Tg. DCs were isolated from single cell suspensions of murine spleen cells by collagenase digestion, density centrifugation and depletion of lymphocytes. Spleen DCs were cultured with HBsAg (100 microg) for 24 h to produce HBsAg-pulsed DCs. HBV-Tg expressing HBsAg and HBV DNA in the sera were randomly assigned to receive either HBsAg-pulsed DCs (n = 20) or unpulsed DC (n = 20) or vaccine containing HBsAg (n = 39) or complete Freund's adjuvant (n = 20) or left untreated (n = 20). Only two intraperitoneal injections of HBsAg-pulsed DCs resulted in negative HBsAg and production of anti-HBs in the sera in all HBV-Tg (n = 20). However, administration of un-pulsed DCs (n = 20) or vaccine containing HBsAg (n = 39) or only complete Freund's adjuvant did not induce negative HBsAg or production of anti-HBs in any HBV-Tg within 6 months of therapy commencement. Taken together, this study showed that HBsAg-pulsed DCs represent a highly potent therapeutic vaccine for chronic HBV infection and inspire optimism of using this vaccine in clinical conditions. A clinical trial of HBsAg-pulsed DC in patients with chronic hepatitis B is warranted.     

Levamisole enhances immune response by affecting the activation and maturation of human monocyte-derived dendritic cells

The primary aim of this study was to evaluate the role of natural killer (NK) cells on antigen-specific adaptive immune responses. After analysing the mechanism of impaired adaptive immune responses of NK-depleted mice, an immune interventional approach was developed to restore adaptive immunity in NK-depleted mice. NK cells were depleted from mice by administration of anti-asialo GM1 antibody (100 mul/mouse), twice, at an interval of 48 h. Hepatitis B surface antigen (HBsAg) was administered intraperitoneally to normal C57BL/6 mice (control mice) and NK-depleted mice. The levels of antibody to HBsAg (anti-HBs) in the sera and HBsAg-specific lymphocytes in the spleen were assessed. The functions of T lymphocytes, B lymphocytes and dendritic cells (DCs) were evaluated in vitro. HBsAg-pulsed DCs were prepared by culturing spleen DCs with HBsAg for 48 h and administered once to NK-depleted mice. The levels of anti-HBs in the sera and HBsAg-specific lymphocytes were significantly lower in NK-depleted mice compared with control mice (P < 0.05). The functions of T and B lymphocytes were similar between control mice and NK-depleted mice. However, the functions of spleen DC and liver DC were significantly lower in NK-depleted mice compared with control mice (P < 0.05). Administration of HBsAg-pulsed DCs, but not HBsAg, induced HBsAg-specific humoral and cellular immune responses in NK-depleted mice. Our study suggests that cross-talk between NK cells and DCs regulates the magnitude of adaptive immunity. In addition, antigen-pulsed immunogenic DCs represent potent immune modulator even if subjects with diminished innate immunity.     

Prognostic importance of antigen-presenting dendritic cells during vaccine therapy in a murine hepatitis B virus carrier

As, the outcome of vaccine therapy was extremely heterogeneous in both human and murine hepatitis B virus (HBV)-carriers, the experiments presented here were performed to find out a prognostic marker of vaccine therapy using an animal model of HBV-carrier state, HBV-transgenic mice (Tg). Neither the prevaccinated titres of viral markers, such as hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg) or HBV DNA, nor the function of lymphocytes prior to vaccination, had significant influence on the outcome of vaccine therapy. Two independent, placebo-controlled, trials of vaccine therapy for 12 months, one in 17 HBV-Tg and the other in 26 HBV-Tg (total, n=43) showed that the eight of 17 and 15 of 26 HBV-Tg that had potent dendritic cell (DC) function at the start of vaccine therapy became completely negative for HBsAg, HBeAg and reduced HBV DNA, whereas all 19 HBV-Tg that had poor DC function at the start of vaccine therapy became complete non-responders, although, the prevaccinated titres of HBsAg, and HBeAg were similar in all 43 HBV-Tg. Further study to find the mechanism underlying this revealed that there was up-regulation of major histocompatibility complex (MHC) class II, CD86 antigens on DC and increased production of interleukin-12 (IL-12) by DC and of IL-2, and tumour necrosis factor-alpha (TNF-alpha) in DC/T-cell cultures when vaccine containing HBsAg was injected in HBV-Tg with potent DC function but not in HBV-Tg with poor DC function. This is the first report on the prognostic importance of DC during an immune therapy. Degree of activation of DC following vaccination would possibly help to predict the outcome of vaccine therapy in human HBV-carriers. These data also provide the scientific and logical basis to up-regulate the function of the DC before an immune therapy.     

Induction of Tc1 response and enhanced cytotoxic T lymphocyte activity in mice by dendritic cells transduced with adenovirus expressing HBsAg

We evaluated the potential of dendritic cells (DCs) engineered to express antigen of hepatitis B virus (HBV) in priming Th/Tc and HBV-specific CTL responses in mice. Recombinant adenovirus expressing hepatitis B surface antigen (HBsAg) (Ad-S) was constructed, and bone marrow-derived DCs were transduced with Ad-S or pulsed with HBsAg protein. Mice were injected with either Ad-S-transduced DCs or HBsAg-pulsed DCs or plasmid DNA encoding HBsAg twice at 3-week intervals. We showed that adenovirus infection had no further effect on the phenotype, the ability to induce IFN-gamma-producing Th1/Tc1 response or the T cell stimulatory capacity of already mature DCs in vitro. We also showed that immunization with Ad-S-transduced DCs effectively induced Tc1 cells and HBsAg-specific CTLs in vivo and down-regulated the circulating HBsAg and HBV DNA in HBV transgenic mice. Furthermore, these efficacies were stronger than that of HBsAg-pulsed DCs and plasmid DNA. Thus, DCs transduced with recombinant adenovirus may be a promising candidate for an effective CTL-based therapeutic vaccine against HBV.     

Anti-idiotypic humoral and cellular responses to antibody to hepatitis B surface antigen in hepatitis B viral infections.

In order to investigate regulatory significance of humoral and cellular responses to the idiotypic (Id) determinants on the antibody to hepatitis B surface antigen (anti-HBs), they were studied in acute hepatitis B and in chronic HBV infection. The results were compared with humoral and cellular responses of the same patients to hepatitis B surface antigen (HBsAg). In acute hepatitis B, the responses to HBsAg, were delayed until 3-4 weeks after the onset of clinical symptoms. However, the leucocyte migration inhibition (LMI) and the lymphocyte transformation (LTT) responses to affinity purified anti-HBs were found to be evolved very early in the course of acute hepatitis B, though anti-Id antibodies were absent. The majority of chronic HBV carriers showed a poor humoral and cellular response to HBsAg. Ten out of 38 chronic carriers showed anti-Id antibodies which recognized a major cross-reactive idiotype (CRI) on the anti-HBs molecule. Twenty-five out of 38 chronic carriers also showed LMI response to the Id determinants on the anti-HBs. LMI response induced by anti-HBs could be blocked by a specific Balb/c anti-Id antibody which also recognized the CRI. Thus, in both acute and chronic HBV infections, the anti-Id humoral and cellular responses correlated with poor humoral and cellular responses to HBsAg, indicating regulatory significance.     

HBsAg脉冲的树突状细胞对CIK细胞功能的影响

目的:探讨HBsAg脉冲的树突状细胞(DC),对细胞因子诱导的杀伤细胞(CIK)的增殖和杀伤作用的影响。方法:选择慢性乙肝患者23例,用常规方法分离外周血单个核细胞(PBMC),经HBsAg脉冲后培养为特异性的DC,用3H-TdR掺入法检测该细胞对CIK细胞增殖的刺激作用,用乳酸脱氢酶释放法检测特异性CIK细胞对HepG2215细胞的特异性杀伤作用。结果:HBsAg脉冲的DC对CIK细胞的增殖具有刺激作用。由HBsAg脉冲的DC所诱导的特异性CIK细胞对HepG2215细胞的特异性杀伤作用增强。结论:HBsAg脉冲的DC可增强CIK细胞的杀伤活性。     

Cell-mediated immunity to hepatitis B surface antigen in man.

An aqueous preparation of hepatitis B virus (HBV) vaccine was used as an intradermal skin test antigen to assess delayed hypersensitivity to hepatitis B surface antigen (HBsAg). Thirty-five persons were tested including 10 individuals seronegative for all HBV markers, 10 positive for HBsAg (chronic carriers) and 15 positive for antibody to HBsAg (anti-HBs), five of whom had received the HBV vaccine. All patients were also studied for lymphocyte blastogenic responses to phytohaemagglutinin, concanavalin A, pokeweed mitogen and purified HBsAg. Only one individual had a positive delayed skin test reaction to HBsAg. This person had received the HBV vaccine and had high titres of anti-HBs in serum. However, neither this individual nor any other subject exhibited a positive lymphocyte blastogenic response to HBsAg in vitro. Thus, delayed hypersensitivity skin test reactivity to HBsAg was not detected after natural infection with HBV and was rarely present in hyperimmunized individuals. In vitro assays of immune responsiveness failed to demonstrate cellular immunity to HBsAg even in hyperimmunized persons. These studies provide no evidence that cell-mediated immunity to HBsAg plays a role in the immunopathogenesis of acute or chronic type B hepatitis.     

Impaired functional capacities of liver dendritic cells from murine hepatitis B virus (HBV) carriers: relevance to low HBV-specific immune responses

The chronic hepatitis B virus (HBV) carrier exhibits ongoing replication of HBV and expresses abundant amounts of HBV-related antigens in the liver. However, HBV-specific immune responses are either absent or narrowly focused in these subjects. With the postulation that impaired functional abilities of liver dendritic cells (DCs) might be responsible for this, we assessed the functions of liver DCs in HBV transgenic mice (HBV-TM), an animal model of the HBV carrier state. Liver DCs were isolated from normal C57BL/6 mice and HBV-TM without the use of cytokines or growth factors. Lymphoproliferative assays were conducted to evaluate the ability of liver DCs to induce the proliferation of allogenic T lymphocytes and hepatitis B surface antigen (HBsAg)-enriched T lymphocytes. Liver DCs were stimulated with viral and bacterial products to assess their cytokine-producing capacities. In comparison to liver DCs from normal C57BL/6 mice, liver DCs from HBV-TM exhibited significantly decreased T cell proliferation-inducing capacities in allogenic mixed leucocyte reaction (P <0.05) and HBsAg-enriched T lymphocytes proliferation assays (P <0.05). Liver DCs from HBV-TM produced significantly lower levels of interleukin-12p70, tumour necrosis factor-alpha, interferon-gamma, and interleukin-6 (P <0.05) compared to liver DCs from normal C57BL/6 mice. This study provides evidence that liver DCs from HBV-TM had impaired ability to induce both innate and adaptive immune responses. This might account for a weak and almost undetectable HBV-specific immune response in chronic HBV carriers. This inspires hope that up-regulation of the functions of liver DCs in situ may have therapeutic implications in chronic HBV carriers.     

Hepatitis B virus DNA in unusual serological profiles of hepatitis B surface antigen-positive sera

On the basis of a seroepidemiological survey of hepatitis B virus (HBV) infection conducted on 6208 random serum samples from four provinces of Thailand, we found 19 of 246 (7.7%) hepatitis B surface antigen (HBsAg)-positive samples with unusual serological constellations of HBV infection. Ten samples tested positive for HBsAg, anti-HBc (anti-hepatitis B core antibody), and anti-HBs (anti-hepatitis B surface antibody) markers (group I), 3 specimens were HBsAg and anti-HBs positive without detectable anti-HBc (group II), and the remaining 6 specimens showed only HBsAg (group III). In group I, 7 of 10 HBsAg-positive sera could be confirmed by HBsAg neutralization, yielding positive results for all samples. None of the group II sera were available in sufficient amounts for confirmation. In group III, five of six sera were confirmed by HBsAg neutralization, with four showing a positive reaction. HBV DNA was detected in 7 of 10 (70%) specimens in group I, in 1 of 3 (33.3%) specimens in group II, and in 3 of 6 (50%) specimens in group III. On the basis of HBsAg neutralization, HBV DNA was found in five of seven (71.4%) HBsAg-positive samples in group I and in three of four (75%) HBsAg-positive samples in group III, whereas the one confirmed HBsAg-negative sample in group III also remained negative for HBV DNA. Amino acid sequences were compared with those specifying the "a" determinant of the wild-type virus, particularly focusing on HBV-S protein variations between positions 110 and 160. Among 11 HBV DNA-positive sera, G145A was detected in 2 samples in group I, with the remaining samples identical to the wild-type virus. These unusual serological profiles may be due to the altered immune response of the host or to HBV variants.     

Neutralization of hepatitis B virus infectivity by a murine monoclonal antibody: an experimental study in the chimpanzee

Two study chimpanzees were inoculated intravenously with approximately 1,000 chimpanzee infectious doses of hepatitis B virus (HBV), one with subtype adr and one with subtype ayw, each previously incubated with 0.1 ml of a murine monoclonal antibody (IgG 1(K) class) directed against a single epitope on hepatitis B surface antigen common to most or all HBV. Two control chimpanzees received identical doses of HBV not incubated with the murine anti-HBs. Neither study chimpanzee developed HBV infection during 12 months of follow-up as judged by normal serum aminotransferase activity, normal liver biopsies, and negative serological tests for HBV-associated antigens and antibodies. In contrast, both control chimpanzees became infected by HBV as evidenced by elevated serum aminotransferase activity, liver biopsy changes characteristic of viral hepatitis, and the appearance of hepatitis B surface antigen (HBsAg) in their sera. Both study chimpanzees were shown to be fully susceptible to infection with these same HBV inocula when challenged 15 months after the initial inoculations at a time when passively administered anti-HBs was no longer detectable. Prior to challenge with HBV, one of the two study chimpanzees received a second injection of the same volume of the murine monoclonal anti-HBs. The survival of this anti-HBs in serum was reduced from six weeks (after the initial injection) to approximately two weeks.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lack of genetic restriction by a potential anti-idiotype vaccine for type B viral hepatitis

Anti-idiotype (anti-Id) reagents that bear an internal image capable of mimicking hepatitis B surface antigen (HBsAg) were used to induce an antibody to HBsAg (anti-HBs) response in both rabbits and chimpanzees. The anti-idiotype induced antibody response produced in rabbits recognized HBsAg determinants associated with the induction of protective immunity against hepatitis B virus (HBV). Attesting further to the specificity was the binding of the rabbit anti-idiotype to the anti-idiotype induced anti-HBs containing sera. Our findings suggest that genetic restrictions associated with the induction of an interspecies immune response may not be a limitation of anti-idiotype based vaccines. In addition, anti-idiotype immunization also produced an anti-HBs in chimpanzees, a species susceptible to infection with human HBV. These data demonstrate that internal-image-bearing anti-idiotype reagents can induce an immune response across species barriers. Additionally, the reagents represent a viable alternative approach to vaccination against agents such as hepatitis B virus that cause human disease.     

Production of antibody to hepatitis B surface antigen (anti-HBs) by murine hepatitis B virus carriers: neonatal tolerance versus antigen presentation by dendritic cells.

The inability of hepatitis B virus (HBV) transgenic mice, which express abundant hepatitis B surface antigen (HBsAg) in sera from the neonatal period onwards, to produce antibody to HBsAg (anti-HBs) is considered to be due to defective function of lymphocytes. The defective function is thought to result from neonatal tolerance because antigenic challenge during the neonatal period is considered to be a tolerogenic event rather than an immunogenic one. However, a series of mixed culture experiments in vitro showed that lymphocytes taken from transgenic mice that had been injected with HBsAg in complete Freund''s adjuvant (CFA) constitutively produced anti-HBs when cultured with dendritic cells from age-, sex- and major histocompatibility complex (MHC)-matched normal mice, but not when cultured with dendritic cells from transgenic mice. The expression of major histocompatibility complex (MHC) class II and B 7.2 (CD86) antigens on dendritic cells was significantly lower in transgenic mice compared with the same from the normal mice (P < 0.05). Treatment of transgenic mice with interferon-gamma (IFN-gamma) resulted in up-regulation of MHC class II on dendritic cells, and lymphocytes from HBsAg-injected transgenic mice produced anti-HBs in vitro when cultured with dendritic cells from IFN-gamma-treated transgenic mice, but not when cultured with the dendritic cells from untreated transgenic mice. These experiments have shown that defective function of antigen-presenting cells (APC), not immunogenic tolerance, is responsible for the inability of murine HBV-carriers to produce anti-HBs. Production of anti-HBs by lymphocytes from HBsAg-injected transgenic mice in the presence of dendritic cells that express higher levels of MHC class II and CD86 antigens has inspired optimism that a more effective vaccine therapy can be developed for chronic HBV-carriers, injecting vaccine containing HBsAg with modulator(s) of APC function of dendritic cells.     

Seroepidemiological studies on hepatitis B and D viruses infection among five ethnic groups in southern Taiwan

In order to compare the prevalence of hepatitis B virus (HBV) and hepatitis D virus (HDV) infection among five ethnic groups in Pingtung County of southern Taiwan, a total of 240 serum samples were collected from September to October, 1985, from the following five ethnic groups: Taiwanese, Hakka, Mainland Chinese, aboriginal Paiwanese, and aboriginal Rukaiese. Ages of subjects ranged from 5 to 69 years. All sera were tested for hepatitis B surface antigen (HBsAg), surface antibody (anti-HBs), and core antibody (anti-HBc) by radioimmunoassay (RIA). Hepatitis B e antigen (HBeAg) and antibody to hepatitis D antigen (anti-HDV) were also tested for those with HBsAg-positive sera. Results showed that 44.1% of all sera examined were negative for HBsAG but positive for both anti-HBs and anti-HBc; additionally, 24.6% were negative for both HBsAg and anti-HBs but positive for anti-HBc. Only 134 serum samples showed negative results for HBV markers, indicating an HBV infection rate of 88.8%. The anti-HDV positive rate was estimated to be 2.7% among HBsAg-positive subjects. The HBsAg-positive rates among Rukaiese, Paiwanese, Hakka, Taiwanese, and Mainland Chinese were 25.8, 22.5, 16.7, 12.9, and 10.0%, respectively; while the prevalence rates of HBV infection among the above five groups were 94.2, 94.6, 85.4, 87.5, and 82.5%, respectively. Differences in the HBsAg-positive rate and HBV infection rate among these ethnic groups were statistically significant. We conclude that people living in Pingtung County are more frequently infected with HBV when compared with inhabitants in northern Taiwan.     

B7-DC-silenced dendritic cells induce stronger anti-HBV immunity in transgenic mice

Hepatitis B virus (HBV) is a noncytopathic DNA virus and is the pathogen of acute and chronic hepatitis. Interferon and nucleotide analogues such as lamivudine and adefovir are the current treatment strategies of HBV infection; however, it is still a serious disease. Therefore, the development of new therapeutic options against HBV is needed. In the present study, we have investigated whether the vectors carrying short hairpin RNA (shRNA) targeting the murine B7-DC gene could silence the expression of B7-DC and analyzed the function of gene-modified dendritic cells (DCs) by mixed lymphocyte reaction. The results demonstrated that two shRNA vectors efficiently suppressed the expression of B7-DC. The MLR assay showed that shRNA-B7-DC-transfected DCs induced markedly higher allogeneic lymphocyte proliferation than transfected DCs with the vector plasmid pAS and untreated DCs at all dilutions. The most efficient shRNA plasmid vector against B7-DC was then used to silence the expression of B7-DC on DCs, the gene-modified DCs were pulsed with HBV-specific peptides, and HBV transgenic mice were immunized. After three rounds of immunization, the splenocytes were stimulated in vitro and tested for cytotoxicitic T lymphocyte activity, while the sera were used to detect the level of HBsAg and HBV DNA. The data demonstrated that blockade of B7-DC on DCs augmented the cytolytic activity induced by immunization with peptide-pulsed DCs and significantly reduced the concentration of serum HBsAg and HBV DNA, suggesting that silencing of B7-DC is of potential value in DC-based therapy of HBV infection.     

Response to hepatitis B vaccine in family members of HBsAg carriers

The family members of HBsAg carriers have an increased risk of hepatitis B virus (HBV) infection. 214 subjects from 98 families with no HBV markers were randomized to receive hepatitis B vaccine: HEVAC B (Institute Pasteur) or GCC VAC (Green Cross Corporation) at 0, 1, and 5 months. Of those who completed the course, 87.8% had an anti-HBs response of greater than 10 mIU/ml at 6 months. The response rate was similar for both sexes. There was a decrease in response rate and anti-HBs titre with age. The response rate for HEVAC B was 92.5% and GCC VAC 84.3%. The offspring had comparable response to the spouses who were not blood relatives of the index carriers, but this could be related to their younger age. Discriminant analysis showed that a higher anti-HBs titre was associated with HEVAC B, younger age, and less direct relationship with the index carrier.     

Influence of hepatitis delta virus superinfection on the clearance of hepatitis B virus (HBV) markers in HBV carriers in Japan

To elucidate the influence of hepatitis delta virus (HDV) superinfection on the clearance of hepatitis B virus (HBV) associated antigens in HBV carriers, we examined for antibody to hepatitis delta antigen (anti-HD) serial sera collected from 1,029 HBV carriers in Kure, Japan. Of the 242 HBV carriers with hepatitis B e antigen (HBeAg), 28 became seropositive for anti-HD, of whom 18 (64.3%) cleared HBeAg; 214 did not become seropositive for anti-HD, of whom 70 (32.7%) cleared HBeAg. Thus, HBeAg clearance was observed in a significantly higher proportion of HDV-superinfected carriers as compared with carriers without HDV infection (P less than 0.005). In the 56 HBV carriers who cleared hepatitis B surface antigen (HBsAg), anti-HD was detected in three cases with increased serum alanine aminotransferase activity preceding HBsAg clearance. The duration of anti-HD seropositive state was less than 5 years, and the titer of anti-HD was relatively low in every case. These data suggest that the HDV infection rate in Japan is higher than previously reported, that HDV superinfection can be one of the factors that induce the HBeAg clearance and HBsAg clearance in HBV carriers, and also that the most likely outcome of HDV superinfection in HBV carriers in Japan may be acute self-limited infection.     

The clinical relevance of the antibody to hepatitis B core antigen (anti-HBc): A review

The antibody against the core component of the Dane particle (anti-HBc) is generally detected in the sera of individuals with acute type B hepatitis and in chronic HBsAg carriers. While the serological demonstration of HBsAg with or without anti-HBc indicates continued replication of viral antigens, the co-occurrence of anti-HBs and anti-HBc is considered a marker of recent HBV replication. The demonstration of anti-HBc in the absence of HBsAg and anti-HBs is in agreement with at least four different states of HBV infection. As this pattern indicates persistent HBV infection in some cases and recovery from an acute type B hepatitis in others, current efforts focus on further characterization of this pattern, using additional test methods such as anti-HBe and anti-HBc of the IgM class.     

Correlation between HBV DNA detection by polymerase chain reaction and Pre-S1 antigenemia in symptomatic and asymptomatic hepatitis B virus infections

The presence of hepatitis B virus (HBV) genome in sera from 73 symptomatic and asymptomatic HBsAg carriers was studied by the polymerase chain reaction (PCR) with primers specific for the S and C regions. Pre-S proteins of the HBV envelope were detected in serum by a specific monoclonal antibody in a double immunoradiometric assay. Out of twenty-five symptomatic patients with chronic active hepatitis (14 with HBeAg and 11 with anti-HBe), all were positive for HBV DNA by PCR, while 14/14 HBeAg and 2/11 (18%) of the anti-HBe patients were positive by dot blot hybridization. All but one anti-HBe patient (96%) carried Pre-S1 proteins. Among the asymptomatic HBsAg carriers, HBV DNA was detected by PCR in 14/14 (100%) HBeAg positive patients and in 25/34 (73%) anti-HBe positive patients. Pre-S1 proteins were found, respectively, in 14/14 (100%) and 11/22 (50%) of the same cases tested in parallel. The 20 healthy blood donors devoid of HBV markers and with normal transaminases tested were found negative for HBV DNA using PCR. Out of 12 patients who recovered from acute hepatitis B, all were found negative by PCR analysis after a mean follow up of 1 year after seroconversion to anti-HBs. When serial samples from 2 patients (one with acute hepatitis B, the other with chronic hepatitis B) were tested for the presence of HBV DNA and of Pre-S1 proteins, both markers showed parallel development.(ABSTRACT TRUNCATED AT 250 WORDS)     

HBV S基因修饰树突状细胞疫苗诱导特异性CTL反应的探讨

目的分析腺病毒载体介导HBVS基因修饰树突状细胞（DCs）能否诱导抗HBV特异性CTL反应。方法制备携带HBVS基因的重组腺病毒，分别转染外周血诱导培养的DCs，观察腺病毒转染DCs效率和DCs中HBV抗原的表达；混合淋巴细胞反应测定HBV抗原基因修饰DCs刺激同种异体T淋巴细胞增殖能力；乳酸脱氢酶释放法检测特异性CTL细胞对HepG2 22．1．5靶细胞的杀伤能力。结果腺病毒载体能够高效介导HBVS基因在DCs中表达，且DC细胞形态完整；HBVS基因修饰DCs具有刺激同种异体T细胞增殖能力，同时能诱导抗HBV特异性CTL反应。结论HBVS基因修饰DCs疫苗具有增强抗HBV特异性CTL效应的能力，可能发展为一种新型抗病毒疫苗。