Preparation and adjuvant activity of OCS-DS nanoparticles encapsulating CTA1-DD protein
The recombinant CTA1-DD protein has systemic and mucosal adjuvant functions comparable to intact CT molecules.But it is easily degraded by enzymes or acids in complex physiological environments.In this study,O-carboxym-ethyl chitosan(OCS)and dextran sulfate(DS),which also had adjuvant activity,were used as carriers to form nanoparti-cles through ion crosslinking,and CTA1-DD protein was embedded in them for stable protection.The particle size of OCS-DS nanoparticles encapsulating CTA1-DD protein ranged from 50 nm to 150 nm,with a Zeta potential of approximately-50 mV.The drug loading rate of OCS-DS nanoparticles encapsulating CTA1-DD protein was 25.33%when 1.0 mg/ml CTA1-DD protein was put into prepara-tion,and the protein encapsulation rate was 86.56%.The simulated release tests in vitro showed that CTA1-DD pro-tein could be slowly released within seven days.The mice were inoculated intranasally with the mixture of CTA1-DD protein and PRV inactivated antigen.The results showed that OCS-DS nanoparticles encapsulated with CTA1-DD protein could simultaneously induce higher expression of serum IgG an-tibodies and mucosal IgA antibodies,which proved its high efficiency as mucosal adjuvant.