ABSTRACT
Objective To investigate immune responses and protective effect induced by two recombinant proteins of hepatitis C virus(HCV)in BALB/c mice.Methods BALB/c mice were immunized with recombinant proteins HCV-T and(or)HCV-F4HVR1 three times.Specific antibodies in sera were tested by enzyme-linked immunosorbent assay(ELISA).Five mice were sacrificed after 14 days of the last immunization.Splenic cells were isolated and levels of interferon(IFN)-γ,interleukin(IL)-4 and cytotoxic T lymphocyte(CTL)cytotoxicity assay were measured in vitro.The remaining mice were subcutaneously injected with 1.0×106 SP2/0-NS3 cells on the back to investigate the protective effects.The differences of means between groups were compared by LSD-t test.Results Compared with phosphate bufter saline(PBS)group,combined immunization with HCV-T and HCV-F4HVR1 induced higher levels of specific IgG against HCV-F4HVR1(t=3.815,3.762,P＜0.05),HCV-NS3-specific CTL response(t=3.971,P＜0.05)and IL-4(t=3.512,3.417,P＜0.05)and IFN-γ(t=3.813,3.426,3.671,P＜0.05)secretions.Conclusion High levels of specific humoral immunity and cellular immunity are induced in vivo after combined immunization with HCV-T and HCV-F4 HVR1,which could effectively prevent from the attack of SP2/0-NS3 cells.
ABSTRACT
Objective To research CpG and Al(OH)3 adjuvants enhancing immunogenicity of hepatitis C virus(HCV) recombinant ptotein combined vaccine(TIE).Methods BALB/c mice were immunized with candidate vaccine TFE using CpG,Al(OH)3,Al(OH) 3 + CpG,or freund's adjuvant(FA) as the adjuvant.Five mice were sacrificed after 10 d of the last immunization.Specific antibodies in sera were tested by enzyme-linked immunosorbent assay(ELISA).Splenic cells were isolated and levels of IFN-γ,IL-4 and cytotoxic T lymphocyte(CTL) cytotoxicity assay were messuredin vitro.The remaining mice were subcutaneouly injected with 1 × 106 SP2/0-NS3 cells on the back to investigate the protective effects.The differences of means between groups were compared by LSD-t test.Results The specific CTL activity of TFE + A1(OH) 3 + CpG group was higher than TFE + FA group and TFE + CpG group(P ＜ 0.05).The level of IFN-γsecreting cells in TFE + Al(OH)3 + CpG group was higher than that in TFE + M(OH)3 group or TFE + CpG group(P ＜ 0.05).Conclusion Combining Al(OH) 3 and CpG could enhance specific cellular immunogenicity of candidate HCV vaccine TFE.TFE + M(OH) 3 + CpG could effetively prevent the attack of tumor cell SP2/0-NS3 expressing nonstructural protein NS3 of HCV.
ABSTRACT
Objective To construct the recombinant plasmid of fusion protein containing respiratory syncytial virus (RSV) cytotoxicity T lymphocyte (CTL) epitope M2:81-95 and heat shock protein (HSP) 70L1, and to investigate its immunogenicity after prokaryotic expression. Methods HSP70L1 gone was cloned from SMMC7721 cells. The M2:81-95 gene fragment was amplified by polymerase chain reaction (PCR) method. Plasmid pET-HSP70L1-M2 : 81-95 (pET-HSP70L1-M2) was constructed, identified and transferred into E. coli BL21 (DE3). Expression of HSP70L1-M2 : 81-95(HSP70L1-M2) was induced by isopropy-β-D-thiogalaetosidc (IPTG). The expressed protein was purified by affinity chromatography and renatured by gradient dialysis. The BALB/c mice were immunized with this fusion protein. IgG antibodies and the subtypes were detected by enzyme-linked immunosorbent assay (ELISA), and CTL responses were determined by methyl thiazolyl tetrazolium (MTT). Results The recombinant plasmid pET-HSP70L1-M2 was successfully constructed. The fusion protein HSP70L1-M2 was expressed in E. coll. The purified protein induced strong RSV-and CTL epitope-specific CTL responses and high titer of protein specific lgG antibody 4.87±0.35. The subtypes were IgG1 (5.53±0.28) and lgG2a (4.40±0.21) and IgG1/ IgG2a ratio was balanced. The titers of lgG, IgG1 and IgG2a in PBS control group were 0.33±0.17, 0.51±0.21 and 0, respectively, which werc significantly lower than those in immunized group (t = 3.512, 3.681, 5.856; P<0.05). Conclusions The recombinant plasmid pET-HSP70L1-M2 is successfully constructed and the fusion protein is expressed and purified. HSP70L1-M2 induced strong RSV-and CTL epitope-specific CTL responses and mixed T helper cell (Th)1/Th2 response in BALB/c mice.
ABSTRACT
Objective To investigate the cellular and humoral immune responses and protective effect induced by co-immunization with two multi-epitope combinant antigens. Methods Mice were co-im-munized with the muhi-epitope HCV-T and HCV-E1 antigens three times. Sera antibodies IgG, IgG1 and IgG2a were tested by ELISA. Spleens from BALB/c mice immunized were removed 10 days after the last im-munization. CTL activity was assessed using LDH cytotoxicity assay kit. IFN-γ- and IL-4-secreting cells were quantified using ELISPOT kit. Two weeks after the final immunization, the mice were challenged sub-cutaneously(s, c. ) at the back with 106 SP2/0-NS3 cells, and protective effect was observed. For therapy, 106 SP2/0-NS3 cells were implanted into the back of BALB/c mice. Seven days later, mice were immuniza-tion three times. Therapy effect was observed. Results Co-immunization with HCV-T and HCV-E1 induced high tiers of HCV-El-specific IgG, IgG1 and IgG2a antibodies, and high level of CTL activity. Synergistic effect in frequencies of both specific IFN-γ-secreting cells and IL-4-secreting cells was observed in mice co-immunized. Prophylactic as well as therapeutic administration of mT + mE1 in mice led to protecting mice against SP2/0-NS3 cells. These results suggested that mT + mE1 was potential as a prophylactic as well as therapeutic HCV vaccine. Conclusion Co-immunization with HCV-T + HCV-EI induced protective humor-al and cellular immune response. HCV-T + HCV-E1 was potential as a recombinant HCV vaccine.
ABSTRACT
Objective:To investigate whether His-tag to change the immunogenicity of recombinant protein G1F/M2 of respiratory syncytial virus.Methods:The G1 and F/M2 gene fragments were amplified by PCR method and then ligated into the expressing vector pET-His or pET-DsbA-His.Each recombinant plasmid was transferred into E.coli BL21(DE3) and the expression was induced by IPTG.The expressed His-G1F/M2 or DsbA-His-G1F/M2 was purified by affinity chromatography.The latter was digested with thrombase and G1F/M2 was purified by affinity chromatography.His-G1F/M2 or G1F/M2 was used to immunize BALB/c mice.Anti-RSV antibody was measured by ELISA and RSV-specific CTL responses by MTT.Results:No significant difference was observed between the level of anti-RSV antibody or RSV-specific CTL response induced by G1F/M2 and that by His-G1F/M2.Conclusion:His-tag does not change the immunogenicity of recombinant protein G1F/M2 of respiratory syncytial virus.
ABSTRACT
Objective: To investigate the regulation of respiratory syncytial virus CTL epitope fused with G protein antigen fragment G1 to the specific immunoresponses. Methods: The recombinant plasmid pET-DsbA-G1 or pET-DsbA-G1F/M2 was transferred into E.coli BL21(DE3) and the fusion protein DsbA-G1F/M2 or DsbA-G1 was expressed.The expressing product was induced and purified by affinity chromatography. The two proteins were used to immunized BALB/c mice i.p, respectively. Serum and spleen cells were collected regularly. RSV-specific CTL responses were measured by MTT, IgG and IgG1 and IgG2a antibodies by ELISA, neutralizing antibodies by plaque reduction assay. Results: The recombinant proteins were expressed successfully and the purity was over 90% after purified by affinity chromatography. The protein DsbA-G1F/M2 induced significant RSV-specific CTL responses, while DsbA-G1 without CTL epitope did not induce detctable CTL responses. Strong IgG antibody responses were elicited,indicated by both. IgG1 and IgG2a titers induced by DsbA-G1F/M2, while only IgG1 was induced by DsbA-G1.The ratio of IgG1/IgG2a was downregulated significantly. Both antigens induced high level of neutralizing antibodies, but the latter was a little lower. Conclusion: DsbA-G1F/M2, the fusion protein of a CTL epitope and G protein fragment G1 can induce both cellular immunity and humoral immunity. The activation of CTLs downregulates the ratio of IgG1/IgG2a.The more balanced immunoresponse is advantageous for improving safety of the candidate vaccine.