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

Abstract

BackgroudPorcine 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.MethodsTo 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-γ 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.ResultsHMSNs 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.ConclusionThe findings suggest that HMSNs are good protein carriers and have high potential for use in future applications in therapeutic drug delivery.

Development of nanoparticle based vaccine delivery systems

“…[30] In addition many research studies have focussed on synthesis, biocompatibility and biodistribution of MSNs. [15,[31][32][33][34][35][36][37][38][39][40][41][42][43][44][45] Various studies have shown that MSNs are excellent vehicles for gene and drug delivery because of their ease of synthesis, surface functionalisation, excellent in vivo biocompatibility as well as good thermal and chemical stability. [40,46,47] Additionally, MSNs are capable of controlling the release of drugs or proteins depending on their size, shape and surface modification.…”

“…At lower concentrations MSNs are found to be non-toxic in a variety of cell lines but at higher concentrations they can have inhibiting effect on cells. [36,115,116] In with the increase in the particle size for 30 min after injection, however, the PEG-MSNs with 360 nm diameter were found to be an exception as they were not captured by spleen within 30 min of injection. This indicates that mostly the organs can easily capture both MSNs and PEGMSNs with larger particle size.…”

“…As the Food and Drug administration (FDA) rarely allows surfactants in injectable drugs, the 100% (w/w) amount of PVA required for complete particle resuspension might not be feasible for vaccine formulations. [36] According to the research carried out by Quintanar-Guerrero et al [37] the best cryoprotectants were sugars for freeze-drying poly(D,L-lactic acid) (PLA)…”

“…[40] Protein encapsulated/adsorbed to silica nanoparticles have been used for the successful delivery of proteins due to their great capability for the entrapment of antigenic proteins. [36,64] Carvalho et al [64] reported that the mesoporous SBA-15 silica acted as an adjuvant in in vivo studies. [64] Uptake studies using HeLa cells demonstrated that MSN could successfully deliver the membraneimpermeable protein cytochrome C in vitro.…”

“…The sustained release of the antigen from the nanoparticles creates a 'depot effect' and enhances the immunogenicity of the adjuvants by producing prolonged immunological response. [34] Nanoparticles such as the polymeric [35], nucleoprotein [36] have been investigated to develop bovine veterinary vaccines and hydroxyapatite nanoparticles have been researched for development of diagnostic tests for cattle infected with…”