Oral and Skin Sensitisation to Peanut Show Different Immunological Features in Brown Norway Rats

Food allergy may develop after both oral and skin exposure to food allergens. Identifying immunological features associated with the sensitisation route is important for understanding the extent to which patients are sensitised through the oral or skin route and may be required to improve food allergy immunotherapy. Thus, the present study aimed at comparing the immunological features of peanut sensitisation induced through the oral and skin route in Brown Norway (BN) rat models. Sensitisation to peanut protein extract (PPE) was induced via oral or skin administration in BN rats. Allergy development was analysed by ELISA for PPE- and major allergen-specific IgE levels and by ear swelling responses to native and denatured PPE. Intestinal and skin tissues were analysed by flow cytometry for immune cell compositions and by TaqMan PCR for the expression of cytokines. Oral and skin sensitisation showed distinct patterns of specific IgE against the major peanut allergens. Conformational IgE epitopes dominated both routes of sensitisation. Skin sensitisation was associated with the activation of T cells and the expansion of antigen presenting cells in both the intestine and skin, whereas oral sensitisation showed a limited effect on immune cell composition and activation. Oral and skin sensitisation were associated with different intestinal cytokine expression profiles. Oral and skin sensitisation drive different responses to the major peanut allergens and promote different immunological responses in the intestine.