利用单个细胞RT-PCR法克隆全人源性HBV单克隆抗体的探讨

目的建立外周血单个抗体分泌细胞分离和单个细胞RT-PCR系统,高效快速克隆高度特异性、全人源性的HBV单克隆抗体。方法选择3例HBV感染恢复期患者,从外周血中富集B淋巴细胞,加入HBcAg Peptide pool活化B淋巴细胞,流式分选出记忆性抗体分泌细胞(CD19~+CD10~-IgG~+CD27~+),通过有限稀释法获得单个细胞,单细胞RT-PCR反转出cDNA,巢式PCR扩增抗体重链恒定区序列片段,将PCR产物纯化并克隆至pEASY~-T1 simple克隆载体,进行测序鉴定。结果 ELISA结果显示,3例HBV感染恢复期患者血浆中均检测到较高水平IgG,与健康志愿者相比,差异均有统计学意义(P值均0.05)。流式结果显示,B淋巴细胞比例均高于94%,且均可分离出记忆性抗体分泌细胞。从分离的抗体分泌细胞中挑选出24个含有1个形态完好的细胞,经鉴定,其中有14个扩增成功,且条带在200 bp左右,与预期片段大小相符。对抗体重链序列分析显示成功扩增出抗体恒定区片段。结论成功构建了单个抗体分泌细胞分离和单个细胞RT-PCR系统,获得了抗体重链序列,为后期全人源性乙型肝炎单克隆抗体的高通量生产打下了坚实的基础。     

Regulation of human peripheral blood erythroid burst-forming unit growth by T lymphocytes and T lymphocyte subpopulations defined by OKT4 and OKT8 monoclonal antibodies

To reexamine the influence that T lymphocytes have on the regulation of human peripheral blood burst-forming unit (BFU-E) proliferation in the absence of a statistically significant number of monocytes, very low numbers (3 to 10 X 10(3)/mL) of a null cell fraction highly enriched for BFU-E were cultured alone and in the presence of 5 X 10(5) sheep erythrocyte-purified, autologous T lymphocytes in a methylcellulose culture system containing erythropoietin. T lymphocytes consistently enhanced the growth of BFU-E from the null cell fraction, as reflected in both their number and size. Irradiation of T lymphocytes prior to coculture with null cells markedly reduced this enhancement, strongly suggesting that T lymphocytes synthesize erythroid burst-promoting factors (BPA). To determine whether there were functional differences between the two major T lymphocyte populations as defined by OKT4 (T helper/inducer) and OKT8 (T suppressor/cytotoxic) murine monoclonal antibodies to stimulate the growth of BFU-E, both T cell subpopulations were isolated by negative (panning) or positive (fluorescence-activated cell sorting) selection and cocultured with null cells. No statistically significant differences emerged between unseparated, OKT4+ and OKT8+ T lymphocytes in their ability to stimulate the growth of BFU-E. Thus, these studies provide further evidence that T lymphocytes are a major population of BPA-producing cells and further that OKT4+ and OKT8+ T lymphocytes equally elaborate these factors.     

Significance of anti-HBx antibodies in hepatitis B virus infection.

Serological responses to hepatitis B virus-X determinants have been noted in human sera, but conflicting findings concerning the correlation of anti-HBx antibodies with different stages of hepatitis B virus infection or pathological sequelae have been reported. Using an adenovirus-based eukaryotic vector, the 17 kD X protein was efficiently expressed in 293 cells. Cellular extracts containing the eukaryotic X protein have been used to screen for anti-HBx antibodies by immunoblot analysis in a large panel of sera from patients affected by hepatitis B virus chronic hepatitis, hepatocellular carcinoma and acute viral hepatitis. Sera from 32 of 171 (19%) chronic hepatitis B virus patients were positive for anti-HBx antibodies. Only one of thirty-two (3%) HBsAg-negative, anti-HBs/anti-HBc-positive chronic hepatitis serum was anti-HBx positive. Very few sera from primary hepatocellular carcinoma patients showed positivity for anti-HBx (8 of 149 or 5%). Anti-HBx were also detected in 8 of 48 (17%) acute viral hepatitis patients. In the four cases that were followed up weekly, anti-HBx antibodies appeared 3 to 4 wk after the onset of the clinical signs. To compare the X protein expressed in eukaryotic and prokaryotic cells as a substrate for anti-HBx antibody detection, 171 sera were screened with HBx fusion proteins expressed in Escherichia coli. The prokaryotic cell extract test seems to be more sensitive. During the chronic phase of hepatitis B virus infection, the presence of anti-HBx antibodies detected with the eukaryotic cell extract correlates with the presence of well-established markers of ongoing viral replication: serum hepatitis B virus-DNA (p less than 0.001) and intrahepatic HBcAg expression (p less than 0.001).     

乙醇与乙型肝炎病毒重叠的肝硬化预后的临床探讨

乙醇与肝炎病毒共同作用已经成为我国东北地区肝硬化患者的第三大原因[1].本研究对乙醇与肝炎病毒共存肝硬化患者的临床预后进行了初步探讨.     

In vitro demonstration of a deficit in suppressor T-cell function in alcoholic cirrhosis. Role of hepatitis B virus infection

The T lymphocyte suppressor cell activity has been evaluated in 33 alcoholic patients compared with 16 normal controls, using an in vitro test. Suppressor T cells were activated with concanavalin A, and suppressor effect was quantified by the inhibition of an autologous B cell culture response to Pokeweed Mitogen. When compared with controls, cirrhotic patients showed a significant defect of suppressor cell activity on B cell production of IgG (20 +/- 3 vs 46 +/- 5 p. 100, p less than 0.001) and IgM (26 +/- 4 vs 56 +/- 8 p. 100, p less than 0.05). In cirrhotic patients, defect of T cell suppressor function was independent of sex and severity of the cirrhosis (Child's staging). This defect was more marked in cirrhotics with serological markers of hepatitis B virus (HBV) infection (n = 11) than in cirrhotics without markers (n = 22) (9 +/- 5 vs 25 +/- 3 p. 100, p less than 0.05; 16 +/- 6 vs 30 +/- 5 p. 100, p less than 0.05 respectively for IgG and IgM production suppression). These results suggest that HBV and lymphocytes interact directly. This interaction could increase the T suppressor cell defect, and explain the promoting role of HBV infection in the constitution of the cirrhosis in alcoholics even when viral replication is not serologically apparent.     

Determination of hepatitis B virus subtypes by an enzyme immunoassay method using monoclonal antibodies to type-specific epitopes of HBsAg

We described a Hepatitis B surface antigen (HBsAg) subtyping method based on a commercial enzyme immunoassay (EIA) for detection of HBsAg in which the procedure was modified to include the use of monoclonal antibodies with restricted anti-HBs specificities. This method, which was able to classify HBsAg as: ayw1, ayw2, ayw3, ayw3 * (intermediate between ayw3 and ayw4 ), ayw4, ayr, adw2, adw4 and adr , was compared to counter electrophoresis procedure (CEP) by testing HBsAg positive sera from blood donors included in a prospective national epidemiological survey. Among the 256 HBsAg positive samples tested with both techniques, 111 (43.3%) could not be subtyped with CEP vs 10 (3.9%) with our modified EIA. This difference was related to the serum HBsAg concentration which must be greater than 3000 ng/mL and 100 ng/mL for CEP and EIA, respectively. The results obtained from 145 sera with both methods were concordant. Seventeen out of 18 samples partially classified as ay with CEP were completely determined with EIA.
This reliable procedure, derived from commercially available reagents, can be easily used in several applications such as large epidemiologic studies and as a substitute for nucleotide sequencing genotyping which is not adapted for large-scale screening and not applicable on samples from nonviremic hepatitis B virus (HBV) carriers.     

Immunological studies on Crohn's disease. V. Enumeration of circulating lymphocytes subsets using monoclonal antibodies

We found normal levels of suppressor cell activity and reduced natural killer (NK) and antibody dependent cell-mediated cytotoxicity (ADCC) activities in patients with Crohn's disease (CD). To further characterize these activities, studies were carried out using monoclonal antibodies. There were no changes in the proportion of OKT4+ (helper/inducer T cells), OKT8+ or Leu 2+ (suppressor/cytotoxic T cells) and Leu 7+ (large granular lymphocytes: LGL, NK + K cells), thereby suggesting that suppressor cell activity in CD is likely to be normal both in function and in number, and that depressed NK and ADCC activities are not due to a reduction in the number of NK or K cells but rather to functional defects. Using a double staining method, we noted a low percentage of both Leu 2 and Leu 7 positive cells in CD.     

Effect of hepatitis C virus infection and abstinence from alcohol on survival in patients with alcoholic cirrhosis

GOALS: We assessed the effect of HCV infection and abstinence from alcohol on survival in a cohort of patients with alcoholic cirrhosis. BACKGROUND: Hepatitis C virus (HCV) infection may be an important cofactor for liver disease in chronic alcoholics. STUDY: The study population consisted of 213 patients with the diagnosis of alcoholic cirrhosis, 72 of these patients were infected by HCV. Complete alcohol abstinence after diagnosis of alcoholic cirrhosis was recorded in 86 patients. The reference group consisted of 89 patients with anti-HCV positivity who had never consumed alcohol. Survival was analyzed by the Kaplan and Meier method and predictors of survival by the Cox's multiple regression model. RESULTS: HCV infection was not a determinant factor for survival in alcoholic cirrhosis. Age and Child-Pugh grade at the time of diagnosis of cirrhosis and persistence of alcohol consumption after diagnosis were independent predictors of poor outcome. The cumulative survival curve in abstinent alcoholics was significantly different from that of alcoholics who maintained the same pattern of alcohol consumption (log-rank = 4.30, p = 0.0381). Moreover, the cumulative survival in patients with anti-HCV-positive cirrhosis who stopped drinking after diagnosis was similar to that in patients with HCV-positive cirrhosis who had never consumed alcohol (log-rank 0.26, p = 0.61). CONCLUSIONS: Cumulative survival in alcoholic cirrhosis does not seem to be influenced by the presence or absence of markers of HCV infection. Once liver cirrhosis has been diagnosed in the alcoholic patient, complete alcohol abstinence should be strongly recommended.     

The dynamic changes of circulating invariant natural killer T cells during chronic hepatitis B virus infection

Aim

The protective role of invariant natural killer T cells (iNKTs) against hepatitis B virus (HBV) infection remains controversial. We sought to clarify the role of peripheral iNKT cells during chronic HBV infection.

Methods

Sixty patients with chronic HBV infection were categorized into an immune tolerance phase (HBV-IT) (n = 16), an immune clearance phase (HBV-IC) (n = 19) and an inactive carrier phase (HBV-IA) (n = 25). Twenty healthy individuals were enrolled as healthy controls. Another 21 HBeAg-positive patients were administrated with entecavir (0.5 mg/day) for 6 months. The percentages of circulating iNKT cells and their IFN-γ and IL-4 expression levels were examined by flow cytometry. The relationships between serum HBV DNA, ALT levels, the percentages of iNKT cells, and their IFN-γ and IL-4 levels were analyzed.

Results

Compared to healthy controls, the percentage of iNKT cells decreased in HBV-IT, but increased in HBV-IC and HBV-IA. Circulating IFN-γ-producing iNKT cells gradually increased, whereas IL-4-producing iNKT cells gradually decreased from HBV-IT stage to HBV-IC and HBV-IA stages. The frequency of iNKT cells and their IFN-γ levels were reversely correlated with viral load. The levels of IL-4 expressed by iNKT cells were positively correlated to viral load and the serum ALT levels. After anti-virus therapy, the percentage of IFN-γ-producing iNKT cells increased while the percentage of IL-4-producing iNKT cells decreased.

Conclusions

During chronic HBV infection, the percentages of peripheral iNKT cells and its cytokines expressions of IFN-γ and IL-4 showed dynamic changes. The expression levels of IFN-γ and IL-4 were correlated with the clearance of HBV and liver injury.

     

Detection of IgM, IgA, and IgG antibodies to preS2 antigen in hepatitis B virus infection.

Antibodies to the preS2 antigen (anti-preS2) of the hepatitis B virus (HBV), including IgA, IgM and IgG classes, were observed in patients with acute and persistent HBV infection. In acute HBV infection, rapid and marked serum IgM and IgA anti-preS2 responses were observed. Antibodies reached a peak of serum activity at about 1-2 months after the onset of clinical symptoms, and both antibodies disappeared from serum at 4 months after. IgG anti-preS2 was detected in the early phase of the illness, then the level of IgG anti-preS2 gradually rose during the recovery phase. In persistent HBV infection, IgG and IgM anti-preS2 were detected in sera where the preS2 antigen was present, and IgM anti-preS2 was significantly higher (p less than 0.05) in HBeAg-positive than in HBeAg-negative patients. These results indicate that an adequate humoral immune response to the preS2 antigen is induced during acute and persistent HBV infection.     

Determination of hepatitis B genotypes in patients with chronic hepatitis B virus infection in Turkey.

BACKGROUND/AIMS: There are significant variations in the geographic distribution of hepatitis B virus genotypes throughout the world, and some genotypes are associated with different clinical outcomes. Eight genotypes of human hepatitis B virus (designated A-H) have been described to date. To determine the hepatitis B virus genotypes in Turkish patients with chronic liver disease and compare the results with clinical characteristics of the patients. METHODS: Fifty-four (pediatric: n=25 and adult: n=29) patients with chronic hepatitis B virus infection and with an hepatitis B virus DNA level above 5 pg/ml were entered into the trial. Restriction fragment length polymorphism method was used to determine hepatitis B virus genotype and their restriction fragment length polymorphism patterns. Hepatitis B virus DNA samples of 13 patients were sequenced automatically for further confirmation of restriction fragment length polymorphism results. RESULTS: Genotype D was the dominant genotype in all of our cases. Among six restriction fragment length polymorphism patterns of genotype D reported in the literature, three (D1, D2, D6) were present in our series and D2 was the most frequent restriction fragment length polymorphism pattern (81.5%). No significant differences were observed among different genotype D restriction fragment length polymorphism patterns with respect to patients' serum ALT, AST, and hepatitis B virus DNA titer, but D2 restriction fragment length polymorphism pattern was significantly more common in younger adults compared to D1 restriction fragment length polymorphism pattern. CONCLUSION: Genotype D with D2 restriction fragment length polymorphism pattern is the dominant hepatitis B virus genotype in all age groups in Turkey.     

Characteristics of hepatitis B X antigen, antibodies to X antigen, and antibodies to the viral polymerase during hepatitis B virus infection

The characteristics of hepatitis B virus (HBV) X antigen (HBxAg) and antibodies against the X antigen (anti-HBx) and the viral polymerase (anti-pol) were determined in 85 HBV-infected patients. HBxAg was detected in sera positive for HBV e antigen (HBeAg) and HBV DNA in patients with acute and chronic hepatitis, while anti-HBx appeared when markers of viral replication became undetectable. HBxAg was common in the liver among patients with chronic hepatitis independent of HBV replication markers but was closely correlated with elevated alanine aminotransferase, implying that HBxAg in liver may be important in the pathogenesis of chronic infection. Anti-pol was detected in many samples positive for HBeAg and HBV DNA and less often in serum samples without markers of HBV replication, suggesting that this marker could reflect ongoing viral replication in the liver, even though such markers were absent from sera.     

Prevalence of antibodies against hepatitis A virus, hepatitis B virus, and Treponema pallidum in Mauritius.

A seroepidemiological study on the prevalence of antibodies against hepatitis A virus (HAV), hepatitis B virus (HBV) and Treponema pallidum was conducted in various groups of the population of the state of Mauritus (Islands of Mauritus and Rodrigues). 618 sera were tested. The overall prevalence of anti-HAV was 86.1% and yielded and age-dependent increase. Serological evidence for acute or chronic HBV infection was found in 3.8%; 4.5% were positive for anti-HBc alone, and in 12.6% past HBV infection was detected. No age- or sex-dependent increase in the prevalence of anti-HBc was found. There were differences in the anti-HBc prevalence among the various groups of population ranging from 5.9 (flight personnel) to 58.3% (prison inmates). Treponemal antibodies were detected in 6.0% and showed a fairly marked age-dependent increase. Our study suggests that vaccination programmes against HAV and HBV would be beneficial for the Mauritian population.     

Role of CXCR5+ CD8+ T cells in human hepatitis B virus infection

The replication of HBV in hepatocytes can be effectively inhibited by lifelong antiviral therapy. Because of the long-term presence of HBV reservoirs, the virus rebound frequently occurs once the treatment is stopped, which poses a considerable obstacle to the complete removal of the virus. In terms of gene composition, regulation of B cell action and function, CXCR5⁺CD8⁺ T cells are similar to CXCR5⁺CD4⁺ T follicular helper cells, while these cells are characterized by elevated programmed cell death 1 and cytotoxic-related proteins. CXCR5⁺CD8⁺T cells are strongly associated with progression in inflammatory and autoimmune diseases. In addition, CXCR5 expression on the surface of CD8⁺ T cells is mostly an indicator of memory stem cell-like failure in progenitor cells in cancer that are more responsive to immune checkpoint blocking therapy. Furthermore, the phenomena have also been demonstrated in some viral infections, highlighting the duality of the cellular immune response of CXCR5⁺CD8⁺ T cells. This mini-review will focus on the function of CXCR5⁺CD8⁺ T cells in HBV infection and discuss the function of these CD8⁺ T cells and the potential of associated co-stimulators or cytokines in HBV therapeutic strategies.     

慢性乙型肝炎患者外周血CD8+T淋巴细胞表面程序性死亡受体-1表达上调的意义

程序性死亡受体-1(PD-1)主要表达于活化的淋巴细胞和单核细胞,尤其是体内活化的T淋巴细胞表面[1],负性调节其活化、增殖和细胞因子的产生[2-3],使人类免疫缺陷病毒(HIV)[4]、HCC[5]、HBV[6-7]等慢性感染过程中患者的病毒特异性CD8+细胞毒性T淋巴细胞(CTL)功能受到抑制,从而造成持续性感染状态.     

Impaired function of CD4+/CD25+ T regulatory lymphocytes characterizes the self-limited hepatitis A virus infection

Background and Aim:  Hepatitis A virus (HAV) causes a transient illness leaving permanent protection against reinfection. Few data are available on the regulatory mechanisms involved in the CD4+ T helper activation. We aimed to investigate the frequency and function of CD3+/CD4+/CD25+ T cells with regulatory function (Tregs) during acute HAV infection.
Methods:  We enrolled 35 consecutive patients and 15 healthy donors, enumerated Tregs by flow cytometry assay and evaluated, after immunomagnetical sorting with magnetic beads, their ability to inhibit the proliferation of CD4+/CD25– T lymphocytes at different ratios (1:1, 1:10, 1:20).
Results:  All patients had the usual course of infection. Our immunological analysis showed Tregs frequency in these patients (6.5% [range, 5–8.8%]; 36 [range, 10–87] cells) did not have any statistical difference compared with healthy donors (6% [range, 5–8%]; 48 (range, 23–71) cells), while their ability to suppress CD4+/CD25– was drastically reduced at different ratios (Mann–Whitney U -test; ratio 1:1, 93% vs 72%, z = −3.34, P  < 0.0001; ratio 1:10, 86% vs 51%, z = −4.04, P  < 0.001; ratio 1:20, 56% vs 30%, z = −3.43, P  < 0.0001). After the seroconversion, CD4+/CD25+ frequency and function in HAV-infected patients did not differ from healthy individuals.
Conclusion:  CD4+/CD25+ T cells seem to be impaired in their function during the HAV acute infection. This evidence might help to determine an optimal T helper cell immune network that is a predisposing factor for a self-limiting disease.     

Diagnosis of Fasciola gigantica infection using a monoclonal antibody-based sandwich ELISA for detection of circulating cathepsin B3 protease

A reliable monoclonal antibody (MoAb)-based sandwich enzyme-linked immunosorbent assay (sandwich ELISA) was developed for the detection of circulating cathepsin B3 protease (CatB3) in the sera from mice experimentally infected with Fasciola gigantica and cattle naturally infected with the same parasite. The MoAb 2F9 and biotinylated rabbit polyclonal anti-recombinant CatB3 antibody were selected due to their high reactivities and specificities to F. gigantica CatB3 antigen based on indirect ELISA and immunoblotting. The lower detection limit of the sandwich ELISA assay was 10, 100 and 400 pg/ml, when applied for the detection of rCatB3 antigen and CatB3 in whole body (WB) of newly excysted juveniles (NEJ) and metacercariae (Met) of F. gigantica, respectively. This sandwich ELISA assay could detect F. gigantica infection from day 1 to 35 post infection and revealed that circulating level of CatB3 peaked at day 1 post infection. In contrast, the antibody detection by indirect ELISA could only demonstrate the antibody level from 35 days post infection. The reliability of the assay method was evaluated using serum samples from mice infected with F. gigantica or Schistosoma mansoni, and hamsters infected with Opisthorchis viverrini, as well as normal mice and hamsters. In addition, sera from cattle infected with Paramphistomum cervi, Strongylid, Trichuris sp. and Strongyloides sp., as well as sera from normal cattle were also assessed. In experimental mice, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, false negative rate and accuracy of ELISA were 95%, 100%, 100%, 97.9%, 0%, 5.3% and 98.5%, while in natural cattle they were 96.7%, 100%, 100%, 98.5%, 0%, 3.4% and 98.9%, respectively. Hence, this assay method showed high efficient and precision for early diagnosis of fasciolosis by F. gigantica.