Construction And Evaluation Of Polymer Nano-vaccine Delivery System Based On Reactive Oxygen Species Response

Vaccine is an antigenic preparation used to prevent infectious diseases.It plays an important role in the prevention and treatment of major infectious diseases and the protection of human beings from invasion.At present,most vaccines are viruses or bacteria and their metabolites that are attenuated or inactivated.They own good immunogenicity,but their stability is poor,and there is safety hidden trouble.Subunit vaccine based on recombinant antigen or peptide has gradually become a novel vaccine,and is an important alternative to traditional vaccines.However,inducing effective immune response is still a major challenge.Nanoparticle antigen delivery system is considered as a potential carrier system to improve the efficacy of subunit vaccine.Infection of the virus and other antigens can cause the increase of lymphocyte reactive oxygen species.Excessive concentration will induce apoptosis of lymphocytes,and the excessive ROS production,especially the excess of hydrogen peroxide,causes inflammation,cell apoptosis and oxidative damage.The use of excessive ROS to cause chronic inflammation,such as inflammation,cancer,and continuous release of ROS after inflammation,is characterized by a higher concentration of disease.The ROS responsive polymer materials are designed to be made into nanoscale carriers to reduce the concentration of ROS at the site of the lesion and to achieve a targeted delivery vaccine.Therefore,we explored whether reactive oxygen responsive nanoparticles can be effectively used for vaccine delivery.In addition,in view of achieving efficient vaccine delivery,a simple synthetic method is used to prepare two amphiphilic polymer material 3s-PLGA-PO-PEG,using the vaccine adjuvant characteristics of polyethyleneimine and the nano carrier system of CD44 target receptor hyaluronic acid and evaluation in vitro,in order to be more scientific and reasonable.The first part:We designed 3s-PLGA to connect polyethylene glycol through peroxy oxalate bond,and prepared the cationic immune adjuvant PEI modified reactive oxygen species nano vaccine.The hydrogen peroxide clearance experiment proved the reactive oxygen response of the material.The cytotoxicity test showed that the nanoparticles had good cytocompatibility and reduced the toxicity of PEI.Confocal observation showed that nanoparticles could achieve lysosomal escape and enhance MHC class I pathway delivery.The expression of BMDC stimulated by nano vaccine was higher than that in free OVA group.After immunization with nanoparticles,the proliferation of lymphocytes increased and the expression of IgG increased significantly compared with free OVA.The results show that the active oxygen nanoscale system has a good immune stimulating effect,induced the maturation of dendritic cells in vitro,the T cells in the body mature and the potential of PEI as an immune stimulant.The second part:We used the H2O2 sensitive peroxalate ester bond designed by the immunostimulatory delivery system,the outer surface modification of hyaluronic acid,that is,a CD44 receptor ligand modified by 3s-PLGA-PO-PEG nanoparticles.The release behavior was observed by the in vitro release test.In vivo,the in vivo migration was observed and the antibody test in vivo and the T cell immune response were evaluated.Our results indicate that nanoparticles enhance dendritic cell maturation and promote antigen uptake and antigen presentation in vitro.The in vivo immunization experiments further showed that OVA specific antibody production and T cell response were promoted,while T cells with moderate stimulation were produced.HA modified ROS responsive nanoparticles may be an effective antigen delivery system to promote antigen induced immune response.