Samaneh H Shabani, Sedigheh Zakeri, Ali H Salmanian, Jafar Amani, Akram A Mehrizi, Georges Snounou, Yousef Mortazavi and Navid D Djadid
Pasteur Institute of Iran, Iran
Zanjan University of Medical Sciences, Iran
National Institute of Genetic Engineering and Biotechnology, Iran
Baqiyatallah University of Medical Sciences, Iran
Pasteur Institute, France
Posters & Accepted Abstracts: J Bacteriol Parasitol
Statement of the Problem: The majority of malaria vaccine studies have mainly focused on Plasmodium falciparum, but Plasmodium vivax have been ignored. However, P. vivax is able to develop hypnozoites, which increases the morbidity caused by a single infection and sever malaria. Additionally, a vaccine targeting of P. vivax represents a necessary tool when considering the elimination/ eradication goal. Many efforts have been conducted to design a vaccine based on circumsporozoite protein (CSP). Because of limited immunogenicity and less effectiveness of protein-based vaccines, these types of vaccines require adjuvant to induce a protective and long-lasting immune response. In this investigation, we evaluate the immunological potency of two newly designed PvCSP based vaccines in combination with a novel adjuvant system (AS). Methodology & Theoretical Orientation: Both CS127 and CS712 constructs include N- and C-terminal parts and a truncated region containing repeat sequences with different arrangement from both PvCSVK210 and PvCSVK247 subtypes. After expression, purification, desalt and concentration, constructs were formulated with novel AS (NLX, CpG and QS21). 6-8 weeks female C57BL/6 mice were immunized with 3 boosts with 2 week interval. Humoral responses include specific antibodies and subclasses against PvCSP, titration and avidity of antibodies, and cellular responses includes lymphocyte proliferation assay and cytokine profiles were evaluated with ELISA, MTT and cytokine assay, respectively. Findings: Our results show that both constructs are highly immunogenic in C57BL/6 mice. Both candidates in combination with AS induce high levels of antibody against PvCSP with high titration and avidity of Th1 related antibodies. Analysis of the induced T-cells highlighted different cytokine profile with significant secretion of IFN-γ and TH1 responses. Conclusion & Significance: Further clinical investigation is needed of these two candidates in primate models to reach the added value in both immunogenicity and protective efficacy.