T cell proliferation and cytokine secretion to T cell epitopes of Asp f 2 in ABPA patients

The pathogenesis of allergic bronchopulmonary aspergillosis (ABPA) involves specific cytokines secreted by lymphocytes in response to Aspergillus fumi gatus (Af) allergens. To gain information about the lymphoproliferative res ponse and cytokine production against a major Af allergen, Asp f 2, we stud ied Asp-f-2-specific T cell clones (TCCs) from ABPA patients. TCCs were sti mulated with rAsp f 2, its deletion mutants, and synthetic peptides to iden tify the T cell epitope(s) and to understand cytokine production. PBMCs fro m four of five ABPA patients showed proliferation in response to Asp f 2. T hree TCCs from one patient showed higher IL-5 secretion compared to IL-4 an d IFN-gamma. Two TCCs from the second patient showed a mixed Th1/Th2 respon se, as evidenced by production of IL-4, IL-5, and IFN-gamma. An epitope fro m the N-terminal region of Asp f 2 induced only IL-5 secretion. High IL-5 s ecretion might explain the marked eosinophilia observed in ABPA patients. ( C) 2001 Academic Press.