Application of mite allergen to desensitization immunotherapy

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The combination of purified antigens with broader cross-reactivity, rather than single purified antigen, seemed to be suitable for desensitization therapy.A purified antigen fraction has been used at first step of the immunotherapy, which was isolated from a whole mite culture on the basis of potent skin reaction and high reactivity to antisera and patients' sera allergic to mite, and has proved highly therapeutic effects.Moreover, the fraction has elicited no side reaction, induction of asthma and anaphylaxis reaction, so that the fraction has been recognized as a therapeutic antigen with high safety and efficiency.Continuously, we are analyzing relationship between changes in titers of patients' immunoglobulins or antibody subclasses, or in sensitivity of basophils to allergens and the efficacy of the immunotherapy.We also isolated low-molecular-size (LM) antigen (4k) and high-molecular-size (HM) antigens (150-155k) as other characteristic antigens.The LM anttigen with potentially as … More thma-inducible property which is facilely permeable to mucosa cross-reacted with the fraction effective for immunotherapy.The antigen would be fit for structual analysis of mite-allergy specific epitopes and induction of T cell anergy.On the other hand, the HM antigen fractions cross-reactive to the LM antigen possessed high immunogenicity and ability to activate T cells, but not induced anaphylaxis reaction.The antigen fractions might be used for immunotherapy.However, it seemed very difficult to prepare a large quantity of therapeutic antigen with constant composition and stable potency from different batches of mite cultures by only biochemical methods.Thus, we isolated cDNA clones encoding mite allergen and classfied the immunoreactive clones into 9 groups by cDNA cross-hybridization.Among them, expression products, Mag1 (high ability to activate mouse T cell), Mag44 (tropomyosin), and Mag3 (high ability to activate human and mouse T cell) with potent IgE-binding activity, and Mag29 (hsp70) and Mag 124 with less IgE-binding activity, were immunobiochemically characterized in this study. Less