Study of fusion expression effect on conformation and immune activity of polyepitope protein,M.RCAg-1 / 中华微生物学和免疫学杂志

ObjectiveTo explore the effects of vector fusion peptides on the conformation and immune reactivity of recombinant polyepitope antigens,M.RCAg-1.MethodsWe subcloned polyepitope artificial antigen gene,M.RCAg-1,into prokaryotic expression vectors,pDS-ex,that contain different fusion tags at the N-terminus or no any tag by different restriction enzyme cutting site.Three recombinant proteins expressed by these vectors,named P312-1,P312-2,and P312-3,were purified and purity is greater than 95％.Then BALB/c mice were vaccinated with the three proteins formulated with Freund's adjuvant through intranasal.Serum were collected to detect specific antibodies of M.RCAg-1 and individual epitope by ELISA ; natural parasite antigen was recognized by indirect immunofluorescence assay; mouse specific T lymphocyte activation was detected by enzyme-linked immunosorbent spot test (ELISPOT) ; and the growth of Plasmodium falciparum in vitro to evaluate by growth inhibition assay(GIA),and analyze secondary and tertiary structures of recombinant proteins from different expression vectors by bioinformatics and circular dichroism technique.ResultsThe P312-1,P312-2 have almost the same amino acid sequence,and the three proteins have the same immunogenicity in animal models(P＞0.05),however,the different proteins elicited various T-cell responses,the rabbit antibody induced by these proteins showed diverse efficacy in malaria parasite growth inhibition assaysin vitro ( respectively,93.9％,14.7％,54.3％ ).The significant differences of secondary and tertiary structures were shown in recombinant proteins from different expression vectors,analyzed by bioinformatics and circular dichroism technique,which demonstrated the change of protein molecule spaces conformation,and the obviously change of some epitope locations.ConclusionThese results suggest that the expressed polyepitope artificial antigens originating from the different vector fusion peptides indeed affect the protein folding and,subsequently,the epitope exposure.Thus,these proteins are able to induce both distinct humoral and cellular immune responses in animal models,and they affect the efficacy of immune inhibition against the parasite,the enhancement or suppresses.

The research on the immunogenicity and in vitro protective efficacy of a polyepitope Plasmodium falciparum candidate vaccine, M.RCAg-1 formulation with different adjuvants / 中华微生物学和免疫学杂志

ObjectiveTo detect the difference of cytokines and antibodies productions by immunologic system from mice and rabbits vaccinated with the M.RCAg-1 chimeric protein,expressed in E.coli,formulation with different adjuvants,including Freund's adjuvant and three clinically acceptable adjuvants,namely,Al(OH)3,Montanide ISA720 and Montanide ISA51.MethodsSix weeks female BALB/c mice were vaccinated with recombinant protein formulated with different adjuvants through intranasal.Serum were collected to detect specific antibodies of M.RCAg-1 and individual Epitope by ELISA ; natural parasite antigen was recognized by indirect immunofluorescence assay; mouse specific T lymphocyte activation was detected by enzyme-linked immunosorbent spot test (ELISPOT) ; Affinity assay between protein and immune IgG of rabbits with the biosensor,and the growth of Plasmodiumfalciparum in vitro to evaluate by growth inhibition assay(GIA).ResultsDifferent formulation can induce different levels of antibody titers,the effection of ISA51 adjuvant was most closely with Freund's adjuvant,and can induce a higher specific antibody of 11 epitopes within proteins,can effectively stimulate cellular immune response based on the IFN-γ,to avidity Montanide ISA51 adjuvant immune antibodies and M.RCAg-1 protein affinity than the other two adjuvants;and Montanide ISA720 adjuvants and Al (OH)3 adjuvant group in mice can't induce a significant IFN-γresponse(P＞0.05).On avidity assay,the Montanide ISA51 formulation group was better than the other two adjuvants; and Montanide ISA720 and Al (OH)3 adjuvant formulation group can't induce a significant IFN-γresponse in mice(P＞0.05) ; the inhibition rates were 60% and 100% in 3D7 and Dd2 Plasmodium falciparum at a concentration of 2 mg/ml IgG by Montanide ISA51 formulated protein,and IgG of Al( OH)3 formulation could not effectively inhibit the in vitro growth of Plasmodium falciparum( 10% ),while IgG of Montanide ISA720 formulation could not inhibit growth of parasite in vitro.ConclusionBy comparing three clinically acceptable adjuvants and Freund's adjuvant in BALB/c mice and New Zealand rabbit,Montanide ISA51 adjuvants can be acceptable formulated M.RCAg-1 protein induced humoral and cellular immune responses,can be used as one of the candidate adjuvants.

Recombination expression and immunoprotective effects of the P6 outer membrane protein of nontypeable Haemophilus influenzae / 中华微生物学和免疫学杂志

Objective To clone and express recombinant outer membrane protein P6, determine its optimal expression conditions and to investigate the immunoprotective effects of the P6 protein on mice. Methods The P6 gene of nontypeable Haemophilus influertzae(NTHi) was amplified by PCR from the NTHi genome and cloned into expression vector pET-32a (+) to generate the pET-32a-P6 recombinants. They were confirmed by nuclease digestion and sequence analysis. The verified recombinant was transformed into E. coli BL21 (DE3). Its optimal expression conditions were determined such as engineering strains, the concentration of IPTG, inducing temperature, inducing time, different medium etc. The recombinant protein was purified by Q Sepharose~(TM) XL ion exchange and gel filtration chromatography. The protein was analyzed by SDS-PAGE, Western blot and sequencing. BALB/c mice were immunized with recombinant protein be-fore challenged by NTHi through intraperitoneal injection. Then the mortality rate of different group was com-pared. Results The recombinant P6 of NTHi was successfully constructed and expressed in E. coli at a rel-atively high level. The purity was up to 95% after purification. The relative molecular mass of the protein is 14 145. 848. The recombinant protein was confirmed to show specific reaction on the antiserum through Western blot. The animal experiments showed the mortality rates of immunization groups were significantly lower than that of the control group (P < 0.05). Conclusion The successful expression of the recombinant P6 will be very helpful for the further study on development of vaccine, its purified, immunological activity and antibody preparation.

Study on expression,purification and biological characteristics of recombinant human interferon-epsilon in E.coli / 中华微生物学和免疫学杂志

Objective To construct a novel recombinant human IFN-ε,and to analyze its physi-cal,chemical properties and biological characteristics.Methods Human genomic DNA was used as the template to synthesize IFN-ε gene by PCR.The sequence was cloned into plasmid vector pET-32a(+),and the recombinant plasmid pET-32a(+)/IFN-ε was transformed into E.coli BL2l(DE3).The form of ex-pression product was inclusion bodies.After purification and renaturation.high purity active protein IFN-εwas achieved.The final product was tested for its physical.chemical properties and biological characteristics including anti-viral and anti-proliferative acfivities.Results IFN-ε was expressed in inclusion body in E.coli.After the protein renaturation and purification,the purity was more than 95%.The rhIFN-ε protein had a specific anti-viral activity of about 1.2×103 IU/mg.Its anti-poliferative activity is obvious and can in-duce cells to produce anti-viral protein MxA.Conclusion Human IFN-ε protein was expressed successful-ly.and this protein has anti-virus and anti-prolireration activity.