RATIONALE: In order to develop a suitable peanut allergen immunotherapy we need to depict the immune response to different forms of the same allergen.
METHODS: We analyzed protein content and allergen distribution in four different types of peanut extract: crude, crude delipidated, roasted and roasted delipidated. We then identified in the same extracts allergen components using SDS-PAGE technique. Furthermore, we immunized six week-old C57BL/6 mice, intradermal or orally with each extract. Serum and fece samples were obtained on days 0, 7, 14, 21, 28, 35 and 42 after immunization and measured peanut specific IgG1 and IgG2 through indirect ELISA.
RESULTS: Protein content in crude peanut extract was 30% higher than roasted extract. No differences were observed in protein content between lipid and non-lipid extract. When allergens were studied, we only observed a significant increase in Arah3 in roasted peanut extract. Regarding the immune response, all four extracts induced a Th2 response (IgG1) through both administration routes. Intradermal sensitization induced higher IgG1 and IgG2 levels than oral sensitization. Maximum IgG1 and IgG2 peak was reached on the 3rd and 4rd week. Roasted delipidated extract induced a significant stronger immune reaction than the other extracts.
CONCLUSIONS: The immune response seems to be more dependent on the allergen rather than the route of administration. Roasting peanut increases significantly in both intradermal and oral route its allergen potency.