Pilot-scale Production And Immunogenicity Study In Different Adjuvant Formulation Of Plasmodium Falciparum Vaccine M.RCAg-1

As one of the three major infectious diseases in the world, malaria is still a threat to human health. According to the most recent data from WHO, the disease took an estimated627000lives in2012, mostly those of children under five years of age in Africa, this means1300young lives lost to malaria every day. The emergence and spread of drug-resistant parasites and insecticide-resistant Anopheles mosquito vectors make traditional prevention and treatment of malaria a big hurdle, which enhance the demand of safe and cost-efficient therapeutic malaria vaccine all over the world.Vaccines which based on single epitope or some epitopes haven’t made great progress in related researches. Therefore, development of a multiple antigens and epitopes vaccine against Plasmodium falciparum at different stages has become one hotspot in the development of malaria vaccines. Previously, our lab had constructed a polyepitope gene library by using a novel approach named "epitope shuffling" and selected a polyepitope chimeric protein M. RCAg-1. Morever, it had been proved that M. RCAg-1had strong immunogenicity in mice, rabbits and NHPs models and its specific antibodies could inhibit Plasmodium falciparum growth in vitro.Our lab had already got the high expression genetic engineering bacteria of M. RCAg-1. On the basis of previous study, we established an efficient pilot-scale manufacturing technology of M. RCAg-1by cultured M. RCAg-1producing E. coli in30L fermenter and improvement of previous purification technology with the help of the corporations. At the same time, in order to find an efficient adjuvant to increase the immunogenicity of vaccine M. RCAg-1, we selected the TLR4agonist adjuvant GLA (GLA-SE and GLA-AF) which has a potential of clinical application to combine with M. RCAg-1, and then evaluate the immunogenicity of M. RCAg-1in BALB/c mice to find the best adjuvant. In all, our research formed the foundation for the following clinicstudy of M. RCAg-1. This research mainly made the following progress:1. With the help of the corporations, we had successfully established a efficient pilot-scale manufacturing technology of M. RCAg-1. After two-step purification, the final M. RCAg-1was over95%in purity, yield was53.2%.2. We selected the adjuvant GLA-SE which could enhance the immunogenicity of M. RCAg-1more significantly than other formulated adjuvants with M. RCAg-1and determined its immune dose of5μg for mouse is appropriate.3. The BALB/c mice were vaccined by the pilot-scale M. RCAg-1combined with GLA-SE and Freund’s adjuvant. After third immunication, serum antibody and spleen lymphocytes of the mice were analyzed. According to the results, it was preliminarily confirmed that GLA-SE is a prospective adjuvant of vaccine M. RCAg-1.