Alternative Methods of Vaccine Delivery: An Overview of Edible and Intradermal Vaccines

Criscuolo, E.; Caputo, V.; Diotti, R. A.; Sautto, G. A.; Kirchenbaum, G. A.; Clementi, N.

There remain a number of obstacles and drawbacks associated with each antigen delivery platform that still need to be addressed (Table 4 ). Presently there are no FDA-approved compounds for edible vaccination, but new emerging technologies like nanoparticles (NPs) could help to control antigen bioavailability to avoid mucosal tolerance. NPs are particles with a mean size of 10-100 nm (up to 2000 nm), which can be used as carriers and/or adjuvants in vaccine preparation [139] [140] [141] . Moreover, NPs can be targeted to specific cell populations. As an example, NPs can be coated with antibodies recognizing a surface protein on dendritic cells [142, 143] . This approach enabled a more accurate measurement of the quantity of antigen required to elicit an immune response [144] . Finally, a more efficient immunization was demonstrated using NP-based approaches combined with an intradermal vaccine delivery [145] , while oral delivery needed further investigations as they have been tested only in vitro [146, 147] .