Targeted delivery of antigens to the gut-associated lymphoid tissues: 2. Ex vivo evaluation of lectin-labelled albumin microspheres for targeted delivery of antigens to the M-cells of the Peyer's patches.

The purpose of this study was to evaluate the possibility of lectin-coupled microspheres to improve the targeted delivery of protein antigens to the lymphoid tissues of mucosal surfaces. Bovine serum albumin containing acid phosphatase model protein and polystyrene microspheres were coupled with mouse M-cell-specific Ulex europaeus lectin. The coupling efficiency, physical characteristics and the binding capabilities of the microspheres to the follicle associated epithelium of the Peyer's patches were evaluated in vitro and ex vivo in mice intestine. The results showed that coupling of lectin to albumin microspheres did not significantly affect the bioactivity of the encapsulated acid phosphatase model protein. It was also shown that there was preferential binding of the lectin-coupled microspheres to the follicle-associated epithelium. It was concluded from the results of the study that coupling of ligands such as lectin specific to cells of the follicle associated epithelium can increase the targeting of encapsulated candidate antigens for delivery to the Peyer's patches of the intestine for improved oral delivery.