Citation

Background Peanut (PN)-anaphylaxis is potentially life threatening. We previously reported that a Chinese herbal medicine preparation, food allergy herbal formula-2 (FAHF-2), prevented peanut allergy (PNA) in mice when administered during sensitization. Objective To investigate whether FAHF-2 also can prevent anaphylactic reactions when administered to mice with established PNA and, if so, whether protection would persist after cessation of therapy. Methods C3H/HeJ mice sensitized and boosted over 8 weeks with a standard protocol known toestablishPNhypersensitivityreceivedsevenweeksofFAHF-2treatmentorwaterasasham treatment. Mice were subsequently challenged with PN at week 14 (1-day post-therapy) and week 18 (4-week post-therapy) to evaluate the efcacy and persistence of FAHF-2 treatment byassessinganaphylactic scores,core bodytemperaturesandplasmahistaminelevels.Serum PN-specic antibody levels and cytokine proles from splenocytes and mesenteric lymph node (MLN) cells were also determined. ResultsAllsham-treatedmicechallengedatweeks14and18showedanaphylacticsymptoms. In contrast, FAHF-2-treated mice showed no sign of anaphylactic reactions. PN-specic IgE levels in FAHF-2-treated mice also were reduced whereas IgG2a levels were increased. Furthermore, MLN cells from FAHF-2-treated mice produced markedly less IL-4 and IL-5, but more IFN-g, and contained increased numbers of IFN-g-producing CD81 cells as compared with sham-treated mice. Conclusion FAHF-2 treatment established PN tolerance in this model, which persisted for at least 4-week post-treatment. This result was associated with modulation of intestinal T helper type 1 cell (Th1) and Th2 cytokine production, and with increased numbers of mesenteric IFN-g-producing CD81 cells.