Suppression of allergic reactions by royal jelly in association with the restoration of macrophage function and the improvement of Th1/Th2 cell responses

We studied the immunomodulatory effects of royal jelly (RJ), the principal food source of the queen honeybee, In this study, suppression of allergic r eactions by RJ was investigated in DNP-KLH immunized mice (DNP-KLH mice). O ral administration of RJ (1 g/kg) to DNP-KLH mice significantly decreased t he serum levels of antigen-specific Ig E and significantly inhibited DNP-KL H mediated-histamine release from mast cells, resulting in the suppression of immediate hypersensitivity reactions of ear skin. In DNP-KLH mice. IFN-g amma (Th1 cytokine) production from CD4(+) T cells was suppressed and IL-4 (Th2 cytokine) production from CD4(+) T cells was increased as compared to normal mice. On the other hand. RJ improved the balance of Th1/Th2 cell res ponses from Th2-dominant to Th1-dominant. RJ significantly increased GSH le vels in macrophages from DNP-KLH mice, In addition, the administration of R J to DNP-KLH mice increased IL-12 p40 mRNA expression and NO production, an d decreased PG E2 production from macrophages as compared to untreated DNP- KLH mice, These results suggested that RJ suppressed antigen-specific Ig E production and histamine release from mast cells in association with the re storation of macrophage function and improvement of Tn1/Th2 cell responses in DNP-KLH mice. (C) 2001 Elsevier Science B.V, All rights reserved.