Effects of tremella–alginate–liposome encapsulation on oral delivery of inactivated H5N3 vaccine

In this study, we evaluated a system for oral vaccine delivery, consisting of liposomes coated first with a layer of tremella and then with an outer layer of acid-induced alginate. In vitro release studies showed that the triple layer of alginate-tremella-liposomes was more resistant to an acidic pH and modulated the release profiles at an alkaline pH. Transepithelial electrical resistance (TEER) studies revealed that liposomes or tremella-coated liposomes were able to open tight junctions of the Caco-2 cell monolayer. In mice, although serum immunoglobulin G (IgG) was not expected to increase and haemagglutination inhibition showed that antibody levels were still too low to provide sufficient protection, alginate-tremella-liposomes encapsulated virus-induced intestinal secretory immunoglobulin A (s-IgA) production to provide protection against virus infection. In conclusion, an oral virus vaccine entrapped in alginate-tremella-liposomes improved the mucosal antiviral s-IgA response. This system may have potential use as a carrier for oral vaccine delivery.