Abstract

Mucosal immunoglobulin serves as strong first line of defense against highly infectious pathogen transmitted through mucosal routes. Antigen delivery through the oral route has proved to be significant due to its high patient compliance, non-invasiveness and induction of specific mucosal and systemic immune responses. However, the oral route appears to be most challenging for antigen delivery due to several limiting factors such as harsh gastric environment, poor absorption, rapid transit time and emergence of immune tolerance. Novel approaches have been implied to address these problems to induce strong immune responses followed by the antigen administration via oral route. Biodegradable carrier(s) have shown considerable success in the field of oral vaccination in the number of in vivo studies. These delivery vehicles are reported to protect the susceptible antigen from harsh gastric environment. Also, these carriers exhibit immune-adjuvant properties and gets deposited in the immune inductive sites of GIT. Various delivery systems have been explored to attain sizeable results for oral vaccinations. Liposome, noisome, virosome, archaeosome, chochleates, immune stimulating complex (ISCOMs), nanoparticles and microparticles are the potential carrier(s) excelling their potentdelivery abilities. This review summarizes the various antigen delivery strategies explored in the field of oral immunization and the recent patent granted for oral vaccination using these carrier strategies.

Keywords: Oral vaccination, drug delivery system, mucosal immunity, tolerance