Chitosan nanoparticle antigen uptake in epithelial monolayers can predict mucosal but not systemic in vivo immune response by oral delivery

<p>This study compared in vitro and in vivo antigen delivery effects of ultrapure chitosan (CS) chloride. CS nanoparticles were formulated to incorporate ovalbumin (OVA) as a model antigen and characterised for size, charge, OVA complexation and release. The effect of CS:OVA nanoparticles on cell viability, epithelial tight junctions and transepithelial permeation of OVA was tested on Caco-2 monolayer in vitro intestinal model. The system’s ability to elicit immune responses was subsequently tested in vivo. The work confirmed that CS complexes with OVA into nano-size entities. Nanocomplexes displayed favourable delivery properties, namely OVA release and no notable cytotoxicity. CS:OVA markedly enhanced antigen delivery across Caco-2 monolayers. However, the system did not elicit notable in vivo immune responses (some mucosal response was apparent) following oral delivery. The study highlights that a clear effect on antigen permeability across epithelial monolayers in vitro may predict the in vivo mucosal but not systemic immune response following oral delivery.</p>