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Incorporation of biomolecular epitopes to malarial antigens should be explored in the development of straintranscending malarial vaccines.The present study sought to determine safety,immunogenicity and cross-species efficacy of Plasmodium falciparum serine repeat antigen 5 polypeptide co-expressed with epitopes of BacilleCalmette Guerin(BCG),tetanus toxoid(TT) and a chemokine gene.Olive baboons and BALB/c mice were randomly assigned into vaccine and control groups.The vaccine group animals were primed and boosted twice with pIRES plasmids encoding the SERA5 + BCG + TT alone,or with either CCL5 or CCL20 and the control group with pIRES plasmid vector backbone.Mice and baboons were challenged with P.berghei ANKA and P.knowlesi H strain parasites,respectively.Safety was determined by observing for injection sites reactogenicities,hematology and clinical chemistry.Parasitaemia and survivorship profiles were used to determine cross-species efficacy,and T cell phenotypes,Th1-,Th2-type,T-regulatory immune responses and antibody responses were assessed to determine vaccine immunogenicity.The pSeBCGTT plasmid DNA vaccines were safe and induced Thl-,Th2-type,and Tregulatory responses vaccinated animals showed enhanced CD4~+(P<0.01),CD 8~+ T cells(P< 0.001) activation and IgG anti-SE36 antibodies responses(P< 0.001) at week 4 and 8 post vaccination compared to the control group.Vaccinated mice had a 31.45-68.69%cumulative parasite load reduction and 60%suppression in baboons(P<0.05)and enhanced survivorship(P< 0.001) with no clinical signs of malaria compared to the control group.The results showed that the vaccines were safe,immunogenic and conferred partial cross-species protection.
Incorporation of biomolecular epitopes to malarial antigens should be explored in the development of straintranscending malarial vaccines. The present study sought to determine safety, immunogenicity and cross-species efficacy of Plasmodium falciparum serine repeat antigen 5 polypeptide co-expressed with epitopes of Bacille Calmette Guerin (BCG ), tetanus toxoid (TT) and a chemokine gene. Olive baboons and BALB / c mice were randomly assigned into vaccine and control groups. vaccine group animals were primed and boosted twice with pIRES plasmids encoding the SERA5 + BCG + TT alone, or with either CCL5 or CCL20 and the control group with pIRES plasmid vector backbone. Michał and Baboons were challenged with P. berghei ANKA and P. knowlesi H strain parasites, respectively. Safety was determined by observing for injection sites reactogenicities, hematology and clinical chemistry. Parasitaemia and survivorship profiles were used to determine cross-species efficacy, and T cell phenotypes, Th1-, Th2-type, T-regu (P <0.01), CD 8 ~ + T (P <0.01), and Tregulatory responses of vaccinated animals showed enhanced Th1-, Th2-type, and Tregulatory responses vaccinated animals showed enhanced immunogenicity of the pSeBCGTT plasmid DNA vaccines were safe and induced Activation and IgG anti-SE36 antibody responses (P <0.001) at week 4 and 8 post vaccination compared to the control group. Vaccinated mice had a 31.45-68.69% cumulative parasite load reduction and 60% suppression in baboons (P <0.05) and enhanced survivorship (P <0.001) with no clinical signs of malaria compared to the control group. The results showed that the vaccines were safe, immunogenic and conferred partial cross-species protection.