Liposome DNA vaccination for cockroach allergy in mice

RATIONALE: The Chinese herbal medicine, Ling Zhi (LZ) has been used to treat asthma in traditional Chinese medical practice and is a major component in anti-asthma and food allergy herbal formulas.To explore the therapeutic mechanisms of LZ on allergic disorders, we compared the effects of LZ to dexamethasune (Dex) on Th2 polarized splenocytes in vitro.METHODS: Th2 polarized splenocytes were generated from spleens of AKR/J mice following conalbumin (CA) sensitization and challenge.Cells were cultured with CA in the presence or absence of LZ or Dex.Proliferation and cytokine profiles were determined.Cell viability and apoptosis were determined by trypan blue exclusion and TUNEL assays respectively.RESULTS: LZ treatment decreased Ag-induced proliferation (p<0.05vs untreated), and 1L-4 and IL-5 secretion (p<0.05vs untreated), and increased IFN-y secretion (p<0.05vs untreated) by Th2 polarized splenocytes at all tested doses.Dex treatment suppressed IFN-? as well as IL-4 and IL-5 cytokine secretion and proliferation.Furthermore, Dex-treated cultures contained few viable cells (5%), whereas the number of viable cells in LZ-treated cultures was essentially the same as in untreated cultures (60-70%).As expected, numerous cells underwent apoptosis in Dextreated cultures but only a small percent in LZ-treated cultures.CONCLUSIONS: LZ can suppress Th2 cell proliferation and switch established Th2 cells to Th0-1ike cells thereby re-establishing a Thl/Th2 balance.The actions of LZ on Th2 cells are different from Dex, which induced apoptosis and overall immunosuppression, The immunoregulato-:ry effect of LZ may be an important mechanism underlying its therapeutic effect on allergic disorders.