Immune response modulation by recombinant peptides expressed in virus‐like particles
Aspergillus fumigatus, a ubiquitous fungus, is implicated in the pathogenesis of a number of clinically different allergic diseases in man, including allergic broncopulmonary aspergillosis. Peptide‐based immunotherapy may offer an alternative treatment strategy for the management of allergic disease. The objective of this study was to alter the allergen‐specific immune response using dominant T cell epitopes of a major A. fumigatus allergen, Asp f2, expressed in yeast as virus‐like particles (VLP). The T cell epitopes of Asp f2, recognized in mice with an H‐2d background, were determined by producing T‐cell hybridomas. Two dominant T cell epitopes, aa60–71 and aa235–249, were identified and expressed in a yeast VLP system. To induce tolerance VLP‐peptides were injected subcutaneously into mice previously immunized with recombinant Asp f2. The T cell immune response was abrogated totally in 3 weeks following a single injection of VLP but was restored 2 months later following intranasal antigen exposure. T‐cell depletion resulted in the reduction of 20–30% of all antigen‐specific immunoglobulin classes. Thus, recombinant peptides expressed in the VLP system can be used successfully in the modulation of Asp f2‐induced immune response in mice, although a single administration is not sufficient to maintain a state of tolerance for a long period of time.