Pru p 3-Epitope-based sublingual immunotherapy in a murine model for the treatment of peach allergy

Scope: Food-specific immunotherapy (SIT) is a promising treatment for lipid transfer protein (LTP)-syndrome. We propose a novel sublingual-SIT (SLIT) that combines a Pru p 3 T-cell peptide and an oligodeoxyribonucleotide (ODN) with CpG motifs (ODN-CpG) as adjuvants to induce a specific Th1/Treg response. Methods and results: LTP-peach allergic mice were treated sublingually with a combination of a CpG sequence and mono- or tetravalent systems including a Pru p 3 peptide, D-1(Prup3) or D-4(Prup3). Mice were challenged intraperitoneally with Pru p 3 one or three weeks after SLIT and tolerance was assessed. Mice treated with D-1(Prup3)+CpG were protected from anaphylaxis after Pru p 3 challenge. They showed no change in body temperature, lower levels of Pru p 3-specific IgE and IgG1 antibodies and higher levels of sIgG2a compared to the untreated group. They had fewer IgE and IgG1 secreting cells and more sIgG2a secreting cells. Moreover, a significantly lower number of Pru p 3-specific CD4(+)T cells and a higher number of Treg cells were found, alongside a Th1 cytokine pattern. These changes were maintained for three weeks after stopping treatment. Conclusion: D(1)Prup3+CpG represents a promising SIT for food allergy. It is easily synthesized and induces protection from anaphylaxis to Pru p 3 that is maintained for at least three weeks.