N-phosphonium Chitosan As Vaccine Delivery System For Immunization

Chitosan is potential for the adjuvant and nasal mucosal vaccine delivery carrier,but its water insolubility greatly limits its application.In view of the fact that there was no report on N-phosphonium chitosan(NPCS)as vaccine delivery vector currently.Thus,the subject was to synthesize NPCS and study the immune effect induced by its delivery of ovalbumin(OVA).There were 3 main parts in this study:1.Preparation and characterization of NPCS.In this study,NPCS was prepared by grafting small molecule quaternary phosphonium salt(CTPB)onto chitosan(CS),and its chemical properties were characterized.Subsequently its antimicrobial activity and hemocompatibility were tested.The results showed that positive charged NPCS(about 220 nm),which contact angle is 26.6°,had not only good water solubility and antibacterial properties,but also excellent biocompatibility and blood compatibility.2.The immune effect induced by intramuscular immunization with NPCS /OVA formulation.NPCS formulated with OVA,the balb/c mice were subsequently immunized intramuscularly with different vaccine formulations.With the help of 1 mg/m L NPCS/OVA formulation,the uptake rate of OVA by DC2.4 was about 20%,and the OVA intensity at the injection site of mice was attenuated to 0 at day 11.The antigen-specific IgG titer of the vaccinated mice was about 25000,and spleen cell proliferation index was approximately 1.5.The results showed that NPCS-based vaccine formulation could significantly enhance antigen presentation,splenocyte proliferation,IgG antibody titer and cytokine secretion.3.The immune effect induced by intranasal immunization with NPCS/OVA formulation.NPCS/OVA formulation was prepared with different mass ratio.Balb/c mice were immunized intranaslly with different vaccine formulations.The results showed that NPCS/OVA formulaiton with mass ratios of 1:1 or 10:1 could induce significantly enhanced splenocyte proliferation,IgG and IgA antibody titer,cytokine secretion,IFN-γ/IL-4 secreted splenocyte,and the effective memory T cells.In conclusion,NPCS was a positively charged and biocompatible water-soluble chitosan derivative,which not only had good antibacterial properties,but also had the potential to become a vaccine delivery carrier.