Study Of Molecular Characteristics Of Glycosylation And Non-Glycosylation Aspergillus Fumigatus Allergen 2

Member of the genus Aspergillus are opportunistic for cold- and warm- blood animals. They are associated with an impressive spectrum of diseases in humans, ranging from benign colonization of the lung tQ life-threatening diseases such as invasive aspergillosis or allergic bronchopulmonary aspergillosis (ABPA). Aspergillus fumigatus is the etiological agent identified in most of the Aspergillus-related human diseases and therefore of particular clinical relevance. A major problem in diagnosis of A.fumigatus-related complications arises from the lack of standardized fungal extracts. The allergenicity of commercial A.fumigatus extracts depends on many factors including the strain used, growth conditions, harvesting and extraction procedures hampering the development of diagnostic reagents suitable for the discrimination between A.fumigatus-related. diseases. Molecular DNAJRNA technologies and biotechnological procedures allow cloning, characterization and production of large amount of single, highly pure allergens. The development of phage surface display technologies for cloning cDNA has speeded up the isolation of candidate cDNAs encoding allergens. Screening of an A.fumigatus cDNA library displayed on the surface of phage Ml 3 allowed characterization and production of a panel of allergens identified as proteins with known biological function or as allergens without sequence homology to known proteins. They belong to two functional categories: secreted and cytoplasmic proteins. Secreted allergens are recognized by serum IgE of A.fumigatus-sensitized individuals with or without ABPA, whereas nonsecreted allergens are exclusively recognized by serum IgE of ABPA patients. The dissection of IgE-mediated immune responses to single A.fumigatus allergens allows discrimination between ABPA and A.fumigatus sensitization with high specificity and sensitivity demonstrating the power of recombinant allergens for the differential diagnosis of A.fumigatus-related ?0? pulmonary complications. Aspergillus fiimigattis allergen 2 (Asp f 2), a 268 amino acid major allergen from Aspergillusfumigatus (A]), showed strong binding to IgE in the sera of over 90% ABPA patients. When overlapping peptides covering the whole sequence of Asp f 2 were evaluated for IgE binding, nine linear regions were identified spanning the full-length of the allergen molecule. Although the antibody binding sites are sequestered based on the primary, secondary, and tertiary structures, the linear sequence may also be significance particular when such synthetic peptides can bind to the serum or membrane bound antibody. Since T-cell epitopes are predominantly linear, they are of value in understanding the T-cell response and activation cascades. The pathogenesis of ABPA could be better understood by use of these relevant synthetic peptides representing T and B cell epitopes and their binding to specific receptors may lead to better understanding of the regulatory events leading to disease. It world be of significant important to study modulation of T cell responses with different peptides of Asp f 2 as it could give useful information for immunotherapeutic approaches to the treatment, diagnosis and management of the disease. As B-cell recognition and activation is based on the secondary and tertiary structures of allergens and since such structures are lacking in the decamer synthetic peptides, we devised Asp f 2 protei...