Pru p 3 is a member of the LTP (lipid transfer protein) family and the major peach allergen in the Mediterranean area. Although it is important sensitizer and responsible for severe reactions, only sensitized experimental model has been obtained. This may be because priming of antigen presenting cells requires the activation of the innate immune system with adyuvants to generate food allergen specific Th2 cells causing IgE synthesis. We aimed to develop a model of peach anaphylaxis by sensitizing mice with Pru p 3 in combination with LPS (lipopolysaccharide) as an adjuvant.
Four groups of mice were sensitized intranasally during 6 weeks: Non-treated; Treated with Pru p 3; Treated with LPS; Treated with Pru p 3+LPS. After, they were intraperitoneally challenged with Pru p 3 and in vivo parameters and in vitrotests (determination of Pru p 3-specific immunoglobulins by ELISA and cellular responses by both T-cell proliferation and cytokine production) were performed.
Only Pru p 3+LPS group showed anaphylaxis, with the appearance of objective symptoms and a decrease in temperature. In vitro analysis showed a Th2 pattern with an increase of the Pru p 3-specific IgE and IgG1, but not IgG2b. Moreover, we found that Pru p 3 increased levels of cell secreting IgG1 and a specific proliferative response of CD4+T cells.
These results demonstrate that a Pru p 3-specific anaphylactic response can be generated after nasal sensitization to Pru p 3 in combination with LPS, promoting a Th2 response as demonstrated both in vivo and in vitro.