Oral vaccination: where we are?

Abstract

As early as 900 years ago, the Bedouins of the Negev desert were reported to kill a rabid dog, roast its liver and feed it to a dog-bitten person for three to five days according to the size and number of bites [1] . In sixteenth century China, physicians routinely prescribed pills made from the fleas collected from sick cows, which purportedly prevented smallpox. One may dismiss the wisdom of the Bedouins or Chinese but the Nobel laureate, Charles Richet, demonstrated in 1900 that feeding raw meat can cure tuberculous dogs - an approach he termed zomotherapy. Despite historical clues indicating the feasibility of oral vaccination, this particular field is notoriously infamous for the abundance of dead-end leads. Today, most commercial vaccines are delivered by injection, which has the principal limitation that recipients do not like needles. In the last few years, there has been a sharp increase in interest in needle-free vaccine delivery; new data emerges almost daily in the literature. So far, there are very few licensed oral vaccines, but many more vaccine candidates are in development. Vaccines delivered orally have the potential to take immunization to a fundamentally new level. In this review, the authors summarize the recent progress in the area of oral vaccines.

NK Cells Influence Both Innate and Adaptive Immune Responses after Mucosal Immunization with Antigen and Mucosal Adjuvant

“…I n recent years, the mucosal immunization route has emerged as an attractive option for inducing both local and systemic immunity (1)(2)(3). In rodents, tissues involved in the generation of such responses after intranasal (i.n.)…”

Scientific Opinion on Mineral Oil Hydrocarbons in Food

“…Although short term peroral feeding did not give any arthritic reactions in DA rats, the authors speculate that oral administration of adjuvants in conjunction with inflammation of the gut caused by some other agent could parallel the arthritic effects of percutaneous exposure on abraded skin (Sverdrup et al, 1998). Incomplete Freund's adjuvant (containing pristane and n-hexadecane), which is a known adjuvant previously used in human and animal injection vaccines (Cox and Coulter, 1997), have been reported to not demonstrate any significant adjuvant effect after oral coadministration with antigen (Silin et al, 2007).…”

Oral Live Vaccine Strain-Induced Protective Immunity against PulmonaryFrancisella tularensisChallenge Is Mediated by CD4+T Cells and Antibodies, Including Immunoglobulin A

“…To this end, membranous or microfold cells (M cells) are located in the follicle-associated epithelium of intestinal Peyer's patches and have been shown to be specialized in the transport and uptake of luminal antigens for the robust induction of systemic and mucosal immunity (10,28). Targeting of vaccine antigens to M cells has gained considerable attention as a means to deliver effective mucosal vaccines (29,51). Given the success of oral vaccines for human use, including the Sabin polio vaccine and the licensed typhoid vaccine, the oral route of immunization may be important in the development of defined vaccines against pulmonary tularemia (51).…”

“…Targeting of vaccine antigens to M cells has gained considerable attention as a means to deliver effective mucosal vaccines (29,51). Given the success of oral vaccines for human use, including the Sabin polio vaccine and the licensed typhoid vaccine, the oral route of immunization may be important in the development of defined vaccines against pulmonary tularemia (51).…”