Antigens orally presented

Blanas E, Davey GM, Carbone FR, Heath WR A bone marrow-derived APC in the gut-associated lymphoid tissue captures oral antigens and presents them to both CD4+ and CD8+ T cells. J Immunol 2000 164 2890-2896. 

A process termed oral immune tolerance causes a reduction in the peripheral response to an antigen when that antigen is presented orally. This is the basis of an experimental approach to treat type-I diabetes, in which there may be an autoimmune reaction against the blood glucose regulating hormone, insulin. 

Since risk analysis plays an important role in public policy decision making, efforts have been made to devise a means by which to identify, control, and communicate the risks imposed by agricultural biotechnology. A paradigm of environmental risk assessment was first introduced in the United States by Peterson and Arntzen in 2004. In this risk assessment, a number of assumptions and uncertainties were considered and presented. These include (1) problem formulation, (2) hazard identihcation, (3) dose-response relationships, (4) exposure assessment, and (5) risk characterization. Risk assessment of plant-made pharmaceuticals must be reviewed on a case-by-case basis because the plants used to produce proteins each have different risks associated with them. Many plant-derived biopharmaceuticals will challenge our ability to define an environmental hazard (Howard and Donnelly, 2004). For example, the expression of a bovine-specihc antigen produced in a potato plant and used orally in veterinary medicine would have a dramatically different set of criteria for assessment of risk than, as another example, the expression of a neutralizing nonspecihc oral antibody developed in maize to suppress Campylobacter jejuni in chickens (Peterson and Arntzen, 2004 Kirk et al., 2005). 

Hasseus B, Dahlgren U, Bergenholtz G, Jontell M Antigen presenting capacity of Langerhans cells from rat oral epithelium. J Oral Pathol Med 1995 24 56-60. 

An intriguing question concerns the immune response elicited by allergen extracts at the mucosal surface. Some studies, in animal models, provided interesting information the dendritic cells of oral mucosa act as efficient antigen-presenting cells and produce IL-12, which directs the immune response towards a Thl profile away from pro-IgE-Th2 profile [6-8],... 

Eriksson K, Ahlfors E, George-Chandy A, Kaiserlian D, Czerkinsky C Antigen presentation in the murine oral epithelium. Immunology 1996 88 147-152. 

Also epithelial cells—enterocy tes may be APC cells in humans—present antigens to T CD8 lymphocytes, which produce antigen nonspecific TCR (Mayer and Shlien, 1987). In rats, on the other hand, selective immunosuppression has been observed which was dependent on antigen-specific T lymphocytes (Bland and Warren, 1986) releasing TGI P, present in Peyer s patches as soon as within 24-48 h of the intake of small antigen doses (Lider et al., 1989). Occurrence of food tolerance may be due to some haptens, e.g., DNCB (2,4-dinitrochlorobenzene) administered to mice orally, according to Galliaerde et al. (1995). 

---