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

ABSTRACT

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.