ALLERGEN EXTRACTS - ALLERGOIDS - PEPTIDES

Allergen extracts and allergoids are used for hyposensitization of typ e 1 allergic patients. The mechanism of hyposensitization is still not fully understood. T helper lymphocytes (TH) of allergic individuals r espond to allergen stimulation with the synthesis of TH2-type cytokine s (IL-4 and IL-5). This cytokine profile of the TH cells from blood is directed towards a TH0/TH1 pattern with increasing allergen doses. Th e therapeutic use of high allergen doses for desensitization is restri cted by the IgE-mediated side reactions. The IgE reactivity of allerge ns can be strongly reduced by chemical modification to allergoids, whi ch retain their sequence-dependent T cell epitopes. Following the iden tification of B and T cell epitopes, peptides which contain T cell-rea ctive sequences can be used to activate the TH cells. Higher concentra tion of allergoids or T cell-reactive peptides can also stimulate in v itro TH cell to a TH0/TH1 type cytokine profile. T cell-reactive pepti des can induce TH cell anergy under particular conditions.