CD4+CD25+FOXP3+ Tregs and HBV-specific CTLs in peripheral blood from chronic hepatitis B patients

AIM: To investigate the roles of CD4⁺CD25⁺FOXP3⁺ regulatory T cells (Tregs) and HBV-specific cytotoxic T-lymphocytes (CTLs) in peripheral blood from the patients with chronic hepatitis B (CHB).METHODS: Peripheral blood mononuclear cells from 28 patients with CHB and 15 healthy controls were analyzed for Treg frequency using flow cytometry and for HBV-specific CTLs using enzyme-linked immunospot assay (ELISPOT).The clinical data of HBV-infected patients were considered.RESULTS: The frequency of CD4⁺CD25⁺FOXP3⁺Tregs was higher in the patients with CHB than that in the patients of healthy controls (3.14%±0.97% vs 1.95%±0.68%, P<0.05), and a positive correlation was found between Tregs and the DNA levels of HBV (r=0.831, P<0.01).HBV-specific CTLs were detected by ELISPOT in CHB patients and a negative correlation was observed between Tregs and CTLs (r=-0.540, P<0.01).CONCLUSION: Peripheral blood CD4⁺CD25⁺FOXP3⁺ Tregs in CHB patients are increased and closely correlated with the DNA replication of HBV and CTLs, suggesting that the clearance of HBV can be influenced by the inhibition of cellular immunoreaction through Tregs.     

Role of hepatitis B virus in intrahepatic TGF-β1/Smads signaling pathway

AIM:To explore the effects of hepatitis B virus (HBV) on intrahepatic expression of transforming growth factor β1（TGF-β1） and Smads. METHODS:The expression of intrahepatic TGF-β1, HBsAg and HBcAg in control group and chronic hepatitis B (CHB) group was detected by immunohistochemical method.The serum HBV DNA content was determined by real-time PCR. The role of HBV in the expression of TGF-β1, Smad3 and Smad7 in human hepatic stellate cell line LX-2 in vitro was observed by cell culture and Western blotting. RESULTS:The average score of intrahepatic TGF-β1 expression in CHB group was higher than that in control group. With the increase in serum HBV DNA content, intrahepatic TGF-β1 expression was also enhanced. In the HBcAg positive hepatic tissue, there was higher TGF-β1 expression than that in the liver tissue of HBcAg negative. Compared with control group and HBV+anti-TGF-β1 group, HBV caused increased expression of TGF-β1 and Smad3 in HBV group in vitro. No difference of Smad7 protein among control group, HBV group and HBV+anti-TGF-β1 group was observed. CONCLUSION: The expression of intrahepatic TGF-β1 is related to serum HBV DNA and hepatocellular HBcAg in the patients with CHB. HBV-induced liver fibrosis mainly relies on positive regulatory mechanisms of Smad3,and the negative regulation by Smad7 almost does not function.     

Detection and enrichment of T lymphocytes based on cytokine secretion in human mixed lymphocyte reaction

AIM: Detection and enrichment of T lymphocytes after allogeneic PBMNC stimulation according to secreted cytokine were performed in order to explore a new approach for studying allogeneic reactive T lymphocytes. METHODS: The novel cytokine secretion assay (CKSA) was applied to detect T lymphocyte secreting IFN-γ, IL-4 and IL-10 at single cell level in human mixed lymphocyte reaction. IFN-γ secreting T cells were enriched by means of magnetic sorting system. RESULTS: Allogeneic PBMNC stimulation didn't alter the proportion of IL-4 and IL-10 secreting T lymphocytes (which were 0.12%±0.03% and 0.10%±0.03%, respectively), but increased proportion of IFN-γ secreting T lymphocytes (1.12%±0.13%). These IFN-γ- secreting T lymphocytes could be further enriched to 67.3%±10.5% . CONCLUSION: It is feasible to detect significantly increased IFN-γ-secreting T cells after allogeneic PBMNC stimulation based on the novel CKSA technique, and these cells could be efficiently enriched for further use.     

Correlation between HBsAg level and HBV DNA titer during chronic hepatitis B treatment

AIM: Viral load is widely used as an indicator for the diagnosis and monitoring the treatment efficacy of chronic hepatitis B (CHB). Previous studies suggested that the quantity of hepatitis B surface antigen (HBsAg) in serum could be a surrogate marker of serum hepatitis B virus (HBV) DNA level. In this study, we aimed to investigate whether HBsAg level correlates with HBV DNA titer during CHB treatment. METHODS: Sera were collected from 47 CHB patients ［35 male, 12 female, mean age: (35±8) years］ treated for 48 weeks with a monotherapy (pegylated interferon alpha-2a, 18 patients; lamivudine, 15 patients) or a combination therapy (pegylated interferon alpha-2a and lamivudine, 14 patients). Serum samples were obtained at week 0 (just before the treatment), 4, 8, 24, 48 and week 72 (24 weeks after the treatment). HBV DNA was measured with real-time polymerase chain reaction (PCR). HBsAg was quantified with an automated chemiluminescent microparticle immunoassay. RESULTS: The titer of HBsAg correlated with the HBV DNA level in the 18 patients with monotherapy of pegylated interferon alpha-2a and the 14 patients with combination therapy (pegylated interferon alpha-2a and lamivudine). The significant correlation (canonical correlation=0.83) was found. However, no correlation in 15 patients with the monotherapy of lamivudine was observed. CONCLUSION: HBsAg titer correlates with HBV DNA level in CHB patients during the treatment with interferon or interferon and lamivudine, which can be a surrogate marker for monitoring the treatment efficacy.     

Balance of Treg/Th17 in synovium of collagen-induced arthritis rats and impact of TNF-α blockage therapy

AIM: To investigate the balance of Treg/Th17 in synovium of collagen-induced arthritis (CIA) and the impact of tumor necrosis factor α(TNF-α) blockage therapy. METHODS: Rat CIA model was established by bovine II collagen injection. The pathological score was evaluated by HE staining and toluidine blue staining. The TNF-α level in plasma was measured by ELISA. The expression of Treg/Th17 in synovium was detected by double staining immunofluorescence. RESULTS: The plasma level of TNF-α in CIA group was significantly higher than that in control group and TNFR-Fc treatment group (P<0.01), whereas no significant difference was found between TNFR-Fc treatment group and control group (P>0.05). No significant difference between CIA group and control group in the ratio of CD4⁺Foxp3⁺Treg cells/CD4⁺ cells in synovium (23.12%±4.93% vs 24.66%±5.82%, P>0.05) was observed, whereas the ratio in TNFR-Fc treatment group was significantly increased(33.07%±5.14%). The ratio of CD4⁺RORγt⁺Th17 cells/CD4⁺ cells in CIA group was significantly higher than that in control group and TNFR-Fc treatment group (9.74%±2.23% vs 1.00%±0.59%, 5.63%±1.76%, P<0.01). CONCLUSION: Differentiation disturbance of Treg/Th17 exists in the synovium of CIA rats. TNFR-Fc may restore the balance of Treg/Th17 by inhibiting Th17 cell differentiation and inducing the production or accumulation of Treg.     

The effect and mechanism of H. polygyrus infection in T-cell-mediated inflammatory bowel disease in mice

AIM: To investigate the effect and mechanism of Heligmosomoides polygyrus (H. polygyrus) infection in mouse inflammatory bowel disease (IBD) mediated by CD4⁺ helper T-cells. METHODS: Ovalbumin (OVA) -specific CD4⁺ helper T-cells were transferred into SCID (severe combined immunodeficiency) mice to establish an IBD model. The IBD mice were infected by H. polygyrus and sacrificed 14 days later. The histological changes of the colon were observed, and the expression of interferon-gamma (IFN-γ) and interleukin-4 (IL-4) in mesenteric lymph nodes was detected by ELISA and flow cytometry. Additionally, IL-4 monoclonal antibody was intraperitoneally injected into the H. polygyrus-infected IBD mice to block the secretion of IL-4. The IL-4-blocking IBD mice were sacrificed 9 days later and the above indexes were also determined.RESULTS: Compared with the non-infection group, the H. polygyrus-infected IBD mice had more severe colonic lesions, higher level of IL-4 and lower level of IFN-γ in mesenteric lymph nodes (all P<0.05). Compared with the non-blocking group, the H. polygyrus-infected IBD mice with IL-4 blockage had less colonic lesions, lower IL-4 level and higher IFN-γ level (all P<0.05).CONCLUSION: H. polygyrus infection in CD4⁺ T-cell-mediated IBD model promotes inflammation in the early stage probably by inducing the secretion of Th2 cytokine and inhibiting the secretion of Th1 cytokine. The finding suggests that using worms for treatment of IBD needs to be cautious.     

Effect of hepatitis virus B protein on the functions of PBMCs isolated from patients with chronic HBV infection

AIM: To study the effect of hepatitis virus B proteins on peripheral blood mononuclear cells (PBMCs) from patients among various types of chronic hepatitis B virus (HBV) infection.METHODS: 80 patients of various types of chronic HBV infection were observed, including 40 HBeAg positive with abnormal alanine aminotransferase (ALT) (A group), 20 HBeAg positive with persistent normal ALT(B group), 20 HBeAg and HBV-DNA negative with persistent normal ALT level(C group). IL-10, IFN-γ in CD8+CD28+T cells, after stimulation with PHA, HBeAg and HBcAg for 48 h, were inspected respectively in PBMCs.RESULTS: IFN-γ was significantly lower in HBeAg positive patients. IL-10 was significantly higher in HBeAg positive with normal ALT. CD8+CD28+T were significantly lower than others. CONCLUSION: In HBeAg positive group, secretion of cytotoxic T lymphocyte (CTL) and Th1 type cellular immunologic reaction is decreased, Th2 type cellular immunologic reaction is enhanced.     

Relationship between precore/basal core promoter mutations of hepatitis B virus and therapeutic effect of peginterferon α-2b,and changes of mutations before and after treatment

AIM:To investigate the relationship between therapeutic effect of peginterferon α-2b (Peg-IFNα-2b) and precore (PC) region G1896A and basal core promoter (BCP) region A1762T/G1764A mutations of hepatitis B virus (HBV), and the changes of the mutations before and after treatment. METHODS:The patients with HBeAg-positive chronic hepatitis B (CHB) (n=69) were treated with Peg-IFNα-2b for 48 weeks and followed up for 24 weeks. The PC and BCP sequences at baseline and the 72th week were determined using polymerase chain reaction (PCR) and direct sequencing. Serum HBsAg, HBeAg, alanine aminotransferase (ALT) and HBV DNA was quantified in the samples taken at baseline (week 0), during the treatment period (weeks 4, 8, 12, 24, 36 and 48), and during follow-up (weeks 60 and 72). RESULTS:Within the total cohort, wild-type (WT) virus was detectable in only 14 patients (20.29%), and mutants were detected in 55 patients (79.71%). The serum HBeAg level in the patients with mutant virus was significantly lower than that in the patients with WT virus (P=0.024). The proportion of WT, PC mutant, BCP mutant and PC+BCP mutant was significantly changed at baseline and week 72 (P=0.004). No significant difference of HBeAg seroconversion and combined response between patients with WT virus or mutants (PC, BCP and PC+BCP) was observed. CONCLUSION:PC and BCP mutations have no effect on the response of HBeAg-positive CHB patients to Peg-IFNα-2b. The proportion of each mutation was significantly changed before and after treatment.     

HLA-DRB1 genotyping and its relation with chronic HBV infection in patients

AIM: To study the HLA-DRB1 genotype and their relation with HBV infection in Shaanxi Han patients. METHODS: HLA-DRB1 genotyping was conducted in 108 case of chronic HBV infection and 108 health controls as well as 32 asymtomatic HBsAg carriers by using polymerase chain reaction-sequence specific primer method. All the patients, asymtomatic HBsAg carriers and health subjects were residents of Shaanxi district and belonged to Han nationality. The association between HLA-DRB1 genotype and different replication of HBV was also studied. RESULTS: DRB1*04, DRB1*09, DRB1*12 and DRB1*15 were the most common genotypes in Shaanxi Han residents with the frequency of 16.2%, 12.5%, 11.6% and 13.4%, respectively. Compared to 108 health controls, the allele frequency of HLA-DRB1*03 (10.6% of HBV patients versus 3.7% of health controls, odds ratio=3.10; P<0.05) and HLA-DRB1*07 (17.6% of HBV patients versus 9.3% of health controls, odd ratio=2.09; P<0.05) were markedly higher. The allele frequency of HLA-DRB1*15 (13.4% of HBV patients versus 6.9% of health controls, odds ratio=0.48; P<0.05) was obviously lower than than in HBV patients. CONCLUSION: HLA-DRB1*03 and HLA-DRB1*07 are closely related with susceptibility to chronic hepatitis B infection, and DRB1*15 is closely related with resistance to chronic hepatitis B infection. These finding suggest that host HLA class II gene is an important factor determining the outcome of HBV infection.     

The levels of 2′, 5′ oligoadenylate synthetase,interleukin 2 and interleukin 12 in hepatitis B virus infection

AIM: In order to study the effect of endogenous interferon system and Th1 response modes on hepatitis B virus infection, the 2′, 5′ oligoadenylate synthetase (2-5OAS), IL-2 and IL-12 were selected as the research parameters. METHODS: The activity of 2-5OAS in peripheral blood mononeuclear cells was determined by sensitive radioenzymatic assay. IL-2 and IL-12 were determined by ELISA. RESULTS: Compared to normal control, the 2-5OAS, IL-2 or IL-12 were not significantly changed (P>0.05) in the asymptomatic HBsAg carricer group. The 2-5OAS, IL-2 and IL-12 were significantly up-regulated (P<0.01) in the group of acute hepatitis, but in the groups of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma, the 2-5OAS, IL-2, IL-12 were significantly down-regulated (P<0.05). Moreover, with the progression of patient′s conditions and with the complications of liver cirrhosis and hepatocellular carcinoma, the 2-5OAS, IL-2 and IL-12 decreased progressively, the 2-5OAS, IL-2, IL-12 were the lowest in guoups of liver cirrhosis and hepatocellular carcinoma (vs each groups of chronic hepatitis, P<0.05). CONCLUSION: The endogenous interferon system and Th1 response are significantly alterable in the different period of hepatitis B virus infection and among the different clinical types. The cellular immunity plays an important role in recovery from HBV infection.     

Association between IL-6-572C/G as well as IFNAR1-168G/C and hepatitis B virus infection in populations of Dai and Han ethnicities in Yunnan Province

ATM: To explore the association between IL-6-572C/G (rs1800796) as well as interferon alpha receptor 1 (IFNAR1)-168G/C (rs2257167) and prognosis after hepatitis B virus (HBV) infection in populations of Dai and Han ethnicities in Yunnan Province. METHODS: The blood samples were collected from Dai people and Han people, each nation including 100 healthy controls and 200 infected individuals (100 spontaneous recovery individuals and 100 chronic patients). Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing were used to identify the gene type. RESULTS: In Dai people, no significant difference was found between genetic polymorphism of -572C/G and prognosis after HBV infection. The differences of C and G alleles between spontaneous recovery group and chronic hepatitis B group, and healthy controls and HBV infection group were not statistically significant. Meanwhile, GG and CG genotypes were a vital protective factor for the person who developed into a chronic heptatitis B patient under the G allele dominance mode (GG+CG/CC) (P<0.05). In Han people, no statistically significance for IL-6-572C/G genotype and allele distribution in each group comparisons had been found, as well as the C allele recessive mode and C allele dominance mode. For the above 4 indicators, no statistically significant difference of IFNAR1-168C/G in Dai and Han people had been found.CONCLUSION: The GG+CG genotype of IL-6-572C/G may be a protective factor for the HBV-infected Dai people to develop into chronic hepatitis B patients. However, there is no significant association between the IFNAR1-168G/C polymorphism and prognosis after HBV infection in the 2 ethnicities.     

Effect of activation of stimulator cells on expression of CD69 by responder T cells in mixed lymphocyte reaction

AIM: To study the influence of status of stimulator cells on activation of responder T cells in mixed lymphocyte reaction (MLR), so as to provide some basis for clinical transplantation. METHODS: Stimulator cells were pretreated differently before mixed lymphocyte culture (MLC) to change their functional status, fluorescence conjugated antibodies and flow cytometry were used to detect expression of CD69 by responder T cells at several different time points.RESULTS:The expression percentages of CD69 by responder T cells in MLCa group(stimulator cells were pre-activated)were significantly higher than those in MLC group(stimulator cells were not pre-activated)at 24,48and 72 hours of culture,respectively(5.21%±0.24%vs 1.98%±0.33%,29.81%±0.85%vs 20.65%±1.00%and 39.61%±1.62%vs 13.49%±0.60%,P<0.01). CONCLUSION: Our results showed that with pre-activated stimulator cells, expression of CD69 by responder T cells could be significantly elevated in MLR.     

Identification of cytotoxic T-lymphocyte epitopes from hepatocellular carcinoma antigen MAGEC2

AIM: To observe whether modified epitopes from hepatocellular carcinoma antigen MAGEC2 have HLA-A2-restricted antitumor ability. METHODS: HLA-A2 epitopes from MAGEC2 protein were predicted by NetCTL 1.2, SYFPEITHI and IEDB. The change of binding anchor motifs by replacing anchor residues created the modified peptides from MAGEC2. The binding affinity of the peptides to HLA-A*0201 molecule was evaluated by T2 cells binding assay. ELISPOT assay and intracellular cytokine staining were used to investigate the ability of the peptides inducing specific restricted cytotoxic T-lymphocytes (CTLs) to release interferon-γ (IFN-γ). The ability of the peptides to induce T-cell response was investigated by cytotoxicity assay in vitro. RESULTS: The candidate peptides P248, P248-1Y, P356, P356-1Y, P356-2L and P356-1Y2L showed moderate affinity toward HLA-A2 molecule. T2 binding assay showed that P248-1Y and P356-1Y2L showed significantly higher affinity for HLA-A2 than the native peptides. ELISPOT assay and intracellular cytokine staining showed P248, P248-1Y, P356 and P356-1Y2L were able to induce specific CTLs to release IFN-γ. ELISPOT assay showed that significantly higher levels of IFN-γ release were induced by P248-1Y and P356-1Y2L than the native peptides. The CTLs induced by P248, P248-1Y, P356 and P356-1Y2L lysed HepG2 cells, and P248-1Y and P356-1Y2L peptide-specific CTLs showed higher cytotoxicity against HepG2 cells than the native peptide-specific CTLs (P<0.05). CONCLUSION: Compared with the native peptides, modified epitopes P248-1Y and P356-1Y2L have higher binding affinity with HLA-A2 and retain immunogenecity. In addition, the antitumor immunity effects of modified epitope P248-1Y and P356-1Y2L are stronger than the native peptides. The peptides P248-1Y and P356-1Y2L are excellent HLA-A2-restricted CTL epitopes from tumor antigen MAGEC2, which could serve as new candidates towards antitumor peptide vaccines.     

Correlation between Toll-like receptor 4 on peripheral blood monocytes and serum IL-6 in patients with chronic severe hepatitis B

AIM:To study the change of Toll like receptor 4(TLR4) on peripheral blood monocytes (PBMCs) and its role in the pathogenesis of chronic severe hepatitis B.METHODS:The expression of TLR4 on CD14+ PBMCs was determined by flow cytometry in 30 healthy control,31 patients with chronic hepatitis B and 30 patients with chronic severe hepatitis B. The level of serum interleukin-6 (IL-6) was detected by ELISA. RESULTS:The expressions of TLR4 on PBMCs and serum IL-6 in the groups of healthy control,patients with chronic hepatitis B and patients with chronic severe hepatitis B were 2.3±1.1,3.7±2.3,6.9±4.1 mean fluorescence intensity (MFI) and （11.5±7.2) ng/L,(40.8±31.2) ng/L,(77.6±33.3） ng/L. The TLR4 value in the group of patients with chronic severe hepatitis B was significant higher than that in the group of healthy control and the group of patients with chronic hepatitis B (P<0.05). However,there was no significant difference between the group of patients with chronic hepatitis B and the group of healthy control (P>0.05). Serum IL-6 increased gradually and significantly between the group of healthy control and the groups of patients with chronic hepatitis B and patients with chronic severe hepatitis B. There was a significant positive correlation between the expression of TLR4 and the content of serum IL-6 in the group of chronic severe hepatitis B. CONCLUSION:TLR4 may play a role in the pathogenesis of chronic severe hepatitis B.     

Differentiation of bone marrow mesenchymal stem cells into cardiomyocyte-like cells in vitro via cardiotrophin 1

AIM: To investigate the effects of cardiotrophin 1 (CT-1) on differentiation of swine bone marrow mesenchymal stem cells (MSCs) into cardiomyocyte-like cells in vitro.METHODS: MSCs were isolated and proliferated from Tibet miniswine. Adipogenic and osteogenic potentials were identified. MSCs were divided into 4 groups for induction: untreated group, 5-azacytidine (5-Aza) group,CT-1 group and 5-Aza combined with CT-1 group. After induction for 4 weeks, the expression of cardiac cell markers including α-actin and cardiac troponin-T (cTnT) was estimated by immunofluorescence staining. Finally, the rates of red fluorescence positive-staining cells were calculated. RESULTS: The expression of α-actin in the 4 groups by red fluorescence staining was as follows: the differentiation rate of cardiomyocyte-like cells in combination group was 29.90%±4.76%, significantly higher than that in 5-Aza group (17.73%±2.34%, P<0.01), CT-1 group (6.63%±0.55%, P<0.01) and untreated group (1.62%±0.09%, P<0.01). The differentiation rate in 5-Aza group was significantly higher than that in CT-1 group (P<0.01) and untreated group (P<0.05). The differentiation rate in CT-1 group was significantly higher than that in untreated group (P<0.01). The expression of cTnT in the 4 groups was as follows: the differentiation rate of cardiomyocyte-like cells in combination group was 36.50%±4.09%, significantly higher than that in 5-Aza group (14.37%±1.65%, P<0.01), CT-1 group (7.50%±0.61%, P<0.01) and untreated group (1.12%±0.23%, P<0.01). The differentiation rate in 5-Aza group was significantly higher than that in CT-1 group (P<0.01) and untreated group (P<0.01). The differentiation rate in CT-1 group was significantly higher than that in untreated group (P<0.01).CONCLUSION: Appropriate concentrations of 5-Aza (10 μmol/L) and CT-1 (0.1 μg/L) induce swine bone marrow MSCs to differentiate into cardiomyocyte-like cells in vitro. CT-1 combined with 5-Aza significantly increases the differentiation rate.     

Antigen-loaded dendritic cells and CD40L triggers the killing effects of cytotoxic T lymphocytes on K562 cells in vitro

AIM:To investigate the anti-tumor effects of special cytotoxic T lymphocytes (CTLs) activated by dendritic cells (DCs) loaded with antigens and CD40L in vitro.METHODS:Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation from normal human heparinized blood.The adherent cells were cultured with granulocyte-macrophage colony stimulating factor (GM-CSF),interleukin-4 (IL-4),alpha tumor necrosis factor (TNF-α),DCs were co-cultured with frozen-thawed antigen of K562 cells and CD40L,then triggered T cells into specific CTLs.RESULTS:Most suspended cells exhibited distinctive morphological features of DCs which expressed CD40 96%,CD86 97%,CD80 77%,CD1a 69%,and gained the powerful capacity to stimulate proliferation of allogenic lymphocytes.Under the effector∶target ratio of 20∶1,CTLs derived from cultures with DCs and frozen-thawed antigen of K562 cells were showed 71.3% cytotoxicities against K562 cells.CTLs derived from cultures with DCs loaded with frozen-thawed antigen and CD40L were showed 86.9% cytotoxicities against K562 cells.Cytotoxicities by CTLs derived from cultures with unloaded DCs against K562 cells were 37.6% and cytotoxicities by monocytes were 21.1%.Cytotoxicities by CTLs derived from experiment groups were stronger than control groups (P<0.05).CONCLUSIONS:The tumor antigen-pulsed DCs induces efficient and specific anti-tumor immunity,CTLs derived from cultures containing DCs pulsed with CD40L show the strongest cytolytic activities on K562 cells.     

Seroprevalence of neutralizing antibodies to human adenovirus type 5, human adenovirus type 26 and chimpanzee adenovirus type 68 in patients with chronic hepatitis B and patients with primary liver cancer

AIM: To investigate the seroprevalence of neutralizing antibodies to human adenovirus type 5 (AdHu5), human adenovirus type 26 (AdHu26) and chimpanzee adenovirus type 68 (AdC68) in the patients with chronic hepatitis B (CHB) and the patients with primary liver cancer (PLC), and to provide guidance for developing safe and effective biotherapy vectors against CHB and PLC. METHODS: The blood samples from 196 patients with CHB and 193 patients with PLC were examined to assess the presence of neutralizing antibodies against AdHu5, AdHu26 and AdC68 by adenovirus neutralization assays. RESULTS: The seroprevalence rates of neutralizing antibodies to AdHu5, AdHu26 and AdC68 in the CHB patients were 84.7%, 58.2% and 39.8%, respectively. Among the patients with PLC, the prevalence rates of neutralizing antibodies were as follows: AdHu5, 75.1%; AdHu26, 66.8%; AdC68, 32.1%. CONCLUSION: The prevalence rates and titers of neutralizing antibodies against AdC68 were the lowest among the 3 adenoviruses. Therefore, AdC68 serves as more suitable biological therapy vectors for CHB and PLC than AdHu5 and AdHu26.     

Prostaglandin E2 receptors,EP2 and EP4, regulate expression of surface molecules and cytokines in B-cells of collagen-induced arthritic mice

AIM: To observe the immunoregulatory effects of prostaglandin E₂ receptor (EP) subtypes EP2/EP4 on the B-cells of collagen-induced arthritic(CIA)mice. METHODS: DBA/1 mice were immunized with chicken type II collagen emulsified in Freunds complete adjuvant to induce arthritis. B-cells were isolated from the splenocyte suspension by positive selection using anti-CD19 monoclonal antibody immunomagnetic beads. The expression of MHC II, CD 80 and CD86 was examined by flow cytometry. The mRNA levels of EPs, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α), IL-6, IL-4, IL-10 and transforming growth factor-β (TGF-β) were detected by real-time RT-PCR. RESULTS: The rank of the mRNA levels of EPs was EP2>EP1>EP3>EP4 in B-cells and EP2/EP4 mRNA expression was obviously increased in CIA mice. EP2 antagonists inhibited the expression of MHC II, CD80 and CD86. EP4 antagonist had little effect on CD80. EP2/EP4 antagonists inhibited the mRNA expression of IFN-γ, TNF-α, and IL-6 (P<0.05 or P<0.01) and increased the expression of IL-10 (P<0.01 or P<0.05). Furthermore, the antagonists of EP2 and EP4 also increased the mRNA expression of IL-4 and TGF-β (P<0.01), respectively. CONCLUSION: PGE₂ modulate the pathogenesis of CIA via EP2/EP4 by regulating the expression of surface molecules and cytokines in B-cells. EP2/EP4 may be a new therapeutic target for treating rheumatoid arthritis.     

Study on polarized Th1/Th2 cell in vitro from adult human peripheral blood

AIM: To investigate the details of CD4⁺ T cell polarized to Th1/Th2 in vitro. METHODS: After isolated the PBMCs and blood-plasma from adult human peripheral blood by Ficoll-Hypaque centrifugation, the PBMC culture procedure with or without the self-blood -plasma was applied to polarize T cells in vitro, these cells were polarized by PHA(20 mg/L),non-PHA respectively. The polarized rates of Th cell after 24 h,48 h,72 h were estimated respectively by flow cytometry following two-color immunofluorescent staining. RESULTS: CD4⁺T cell would polarize to Th1/Th2 two subsets after self-cytokines and PHA activation in vitro. The polarized rates of T cell after cultured for 24 h,48 h and 72 h were (13.28%±1.59%)/(12.70%±1.65%),(17.19%±1.03%)/(17.50%±1.30%),(19.49%±2.87%)/(18.58%±1.49%) respectively, but the polarized rates of T cell were very low if without self-blood-plasma. The difference between them was significant. The ratios of Th1/Th2 cells were about 1. CONCLUSION: CD4⁺T cell from adult human peripheral blood would polarize to Th1/Th2 two subsets in the presence of self-blood-plasma and PHA(20 mg/L) in vitro, and the cell number of Th1 and Th2 would be in balance.     

Identification and molecular modification of cytotoxic T-lymphocyte epitopes from osteosarcoma high-expressing antigen PBF

AIM: To observe whether modified epitopes from osteosarcoma high-expressing antigen papillomavirus-binding factor (PBF) have HLA-A2 restricted antitumor ability, and to develop peptide-based immunotherapy for osteosarcoma. METHODS: RT-PCR and Western blot were used to determine the expression of PBF in the osteosarcoma cell lines U2OS and Saos-2. HLA-A2 epitopes from PBF protein were predicted by NetCTL 1.2, SYFPEITHI and IEDB. The modified peptides from PBF containing HLA-A2 binding anchor motifs were designed by replacing the anchor residues. The peptides were synthesized by standard solid-phase methods, and the binding affinity of the peptides to HLA-A*0201 was evaluated by T2A2 cell binding assay. ELISPOT assay was used to investigate the seretion of interferon-γ (IFN-γ) from the peptide-induced specific cytotoxic T-lymphocytes (CTLs). The ability of inducing T-cell response was analyzed by lactate dehydrogenase (LDH) release assay and carboxyfluorescein succinimidyl ester (CFSE) cytotoxicity assay in vitro. RESULTS: The expression of PBF was observed in the U2OS and Saos-2 cells. The candidate peptides P75-1Y2L, P412-1Y, P416-1Y2L9V, P107-1Y and P435-1Y2L showed moderate affinity toward HLA-A2 molecule. The modified peptides showed significantly higher affinity with HLA-A2 than the native peptide. ELISPOT assay showed that P412, P412-1Y, P416, P416-1Y2L9V and P435-1Y2L induced specific CTLs to secrete IFN-γ, and P412-1Y and P416-1Y2L9V induced more secretion of IFN-γ than the native peptide. The CTLs induced by P412, P412-1Y, P416 and P416-1Y2L9V lysed U2OS cells. P412-1Y and P416-1Y2L9V peptide-specific CTLs showed higher cytotoxicity against U2OS cells than the native peptide-specific CTLs. CONCLUSION: Compared with the native peptide, modified epitopes P412-1Y and P416-1Y2L9V have higher binding affinity with HLA-A*0201 and retain immunogenecity. In addition, the anti-tumor immunity effects of modified epitopes P412-1Y and P416-1Y2L9V are stronger than the native peptide. The peptides P412-1Y and P416-1Y2L9V is excellent HLA-A*0201 restricted CTL epitopes from tumor antigen PBF, which could serve as new candidates towards antitumor peptide vaccines.