Immunization of mice by Hollow Mesoporous Silica Nanoparticles as carriers of Porcine Circovirus Type 2 ORF2 Protein

Backgroud: Porcine circovirus type 2 (PCV2) is a primary etiological agent of post-weaning multi-systemic wasting syndrome (PMWS), which is a disease of increasing importance to the pig industry worldwide. Hollow mesoporous silica nanoparticles (HMSNs) have gained increasing interest for use in vaccines. Methods: To study the potential of HMSNs for use as a protein delivery system or vaccine carriers. HMSNs were synthesized by a sol-gel/emulsion(oil-in-water/ethanol) method, purified PCV2 GST-ORF2-E protein was loaded into HMSNs, and the resulting HMSN/protein mixture was injected into mice. The uptake and release profiles of protein by HMSNs in vitro were investigated. PCV2 GST-ORF2-E specific antibodies and secretion of IFN-gamma were detected by enzyme-linked immunosorbent assays, spleen lymphocyte proliferation was measured by the MTS method, and the percentage of CD4+ and CD8+ were determined by flow cytometry. Results: HMSNs were found to yield better binding capacities and delivery profiles of proteins; the specific immune response induced by PCV2 GST-ORF2-E was maintained for a relatively long period of time after immunization with the HMSN/protein complex. Conclusion: The findings suggest that HMSNs are good protein carriers and have high potential for use in future applications in therapeutic drug delivery.