Abstract
To induce immunity against infectious diseases, vaccination at mucosal sites represents one of the major inventions in the field of healthcare. Since decades, various mucosal routes including nasal, oral and rectal have been exploited but the oral route is more patient compliance better than others due to its astonishing advantages as mucosal immunity generated by oral vaccines serves as a strong first line of defense. Proper stimulation of the cellular and humoral immune response is vital for the effective protection of mucosal surfaces against invasion of infectious pathogens. Recently, colloidal carriers like liposomes, niosomes, bilosomes, virosomes, ISCOMS, archaeosomes, chochleates, micronanoparticles and dendrimers have shown great attention for delivery of antigenic materials via gastrointestinal route. Moreover, delivery of mucosal adjuvant in combination with these carriers has also been proved as a successful strategy to enhance the stimulation of mucosal immune system. Further, selective and specific delivery of antigen to Peyers patch or any other antigen presenting cells are appropriate for efficient uptake of antigen to and induce enhanced immune responses. In this paper, we have reviewed various carrier systems, immuno-adjuvants and targeting ligands to deliver vaccines efficiently through oral route providing non invasive method of immunization. Some of these have also been evaluated in the pre clinical and clinical trials. In future, these studies could help in developing vaccines at commercial scale having potential of eradicating life threatening infectious diseases.
Keywords: Oral immunization, delivery systems, antigen, M-cell targeting, adjuvant
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