ABSTRACT
Objective To evaluate the immune response triggered by an in-house constructed hu-man metapneumovirus multi-epitope antigen ( MEA) in a mouse model .Methods Female SPF BALB/c mice at age 4-6 weeks were used in the study and divided into 7 groups.Mice in the five groups including MEA+oligodeoxynucleotides containing CpG motifs ( CpG ODN) intraperitoneal injection ( i.p.) treatment group, MEA+Alum i.p.treatment group, MEA+Alum+CpG ODN i.p.treatment group, MEA+CpG ODN intranasal (i.n.) treatment group and MEA+Alum+CpG ODN i.n.treatment group were immunized three times on days 0, 14 and 21, and those in the other experimental group were immunized intramuscularly with MEA+Quickantibody5W on days 0 and 21.A control group without treatment was set up accordingly .All mice were sacrificed two weeks after the last immunization .Antibodies including IgG , IgG1, IgG2a and IgA in serum samples were detected by ELISA .MTS assay was performed to analyze the proliferation of lympho-cytes.The cytotoxicity of cytotoxic T lymphocytes (CTL) was measured by LDH assay.Flow cytometry was used to detect T lymphocyte subsets .The cytokines secreted by T helper cells ( Th1 and Th2) were analyzed with Bio-Rad Liquid Chips.Results High titers of IgG, IgG1 and IgG2a antibodies were produced in MEA treated mice except for those in intranasal treatment groups .Serum samples from three groups including the MEA+Alum i.p., MEA+Alum+CpG ODN i.p.and MEA+Quickantibody5W i.m.treatment groups were positive for IgA antibody .The highest titer of IgA antibody was detected in mice from the MEA+Alum+CpG ODN i.p.treatment group, which was 2.15×103.Compared with the control group, significantly enhanced proliferation of lymphocytes was observed in the MEA+Alum i.p., MEA+Alum+CpG ODN i.p.and MEA+Quickantibody5W i.m.treatment groups (P<0.05).Enhanced cytotoxic activities of CTL were observed in mice with ip.and i.m.treatments as compared with those in control group (P<0.05).The levels of CD4+/CD8+T cells were slightly increased in mice from the MEA+CpG ODN i.p., MEA+Alum+CpG ODN i.p. and MEA+Quickantibody5W i.m.treatment groups as compared with those in control group (P<0.05).In-creased secretion of IL-2, IFN-γand Th2-type cytokines including IL-4, IL-5 and IL-10 were detected in mice from the MEA+CpG ODN i.p.treatment group.The MEA+Alum i.p.treated mice showed a slightly increased secretion of IFN-γand significantly increased secretions of IL-4, IL-5 and IL-10.Significantly in-creased secretions of IFN-γ, IL-4, IL-5 and IL-10 were detected in mice from the MEA+Alum+CpG ODN i.p.treatment group.Significantly increased secretions of IFN-γ, IL-5, IL-10 and granulocyte-macrophage colony-stimulating factor (GM-CSF) were detected in mice from the MEA+Quickantibody5W i.m.treatment group.Conclusion MEA together with different adjuvants could stimulate high titers of specific antibodies , increase the proliferation of lymphocytes and enhance the cytotoxic activities of CTL .CpG ODN could bal-ance the Th1/Th2-mediated immune responses , and the balance could be enhanced when using CpG ODN in combination with Alum .A similar effect could be achieved by using the commercial adjuvant Quickanti -body5w.This study has paved the way for further investigation on the development of hMPV epitope vaccines and diagnostic reagents for hMPV as well as the epidemiological study of hMPV .
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 construct the multi-epitope antigen(mea) gene of G2 glycoprotein of Hantavirus SEO type L99 strain.Methods The B cell epitopes was chosen and connected by three-peptide GPG after the amino acid sequence of G2 protein was analyzed and predicted by bioinformatical soft wares.The corresponding gene mea was constructed by overlap PCR,and cloned into the prokaryotic expression plasmid pET32a(+).Results The mea gene was successfully constructed by the five epitopes being chosen.The recombinant plasmid pET32a-mea was acquired by directional cloning.Conclusion The mea and its expression system E.coli BL21/pET32a-mea were constructed for the first time.The foundation was laid for the expression of the mea and its immunological applications.