A current focus in allergy research concerns several classes of proteins from house dust mice species, implicated as elicitors of the allergic response in asthma. One of these classes of proteins is the group I cysteine proteases. Using molecular biology techniques, allergens coding sequences from this protein have been cloned from Dermathophagoides pteronyssinus, D. farinae and Europhyphus maynei allowing the sequence analysis of potential manipulation of these proteins. The mice specie Blomia tropicalis (BT) is an important source of allergens including allergic asthma in tropical regions. Many studies have been performed to characterize and identify the allergens in extracts from DF and DP. Unfortunately, little work has been done regarding the identification of the spectrum and relative clinical importance of BT allergens. To overcome this limitation the current study proposes to identify and characterize the group 1 allergen (cysteine protease) from BT and to evaluate the antigen's role and specificities of both the native and the recombinant protein with its natural counterparts and its potential use for diagnostic procedures. The native protein will be isolated from faecally enriched extracts by affinity chromatography. PCR will be applied to amplify sequences from a cDNA library of BT (lambda gt 22A), prior to cloning and sequencing. The recombinant protein will be expressed using a prokaryotic or an insect expression vector. The enzymatic activity of both the native and the recombinant proteins will be identified and characterized by substrate hydrolysis, pH performance and inhibition studies which allow comparison of these proteins. The antigenic role and specificities of the proteins will be evaluated using sera from atopic patients. The use of recombinant allergens will facilitate clinical and immunological studies of the role of B1 in asthma, and offer the prospect of developing new strategies for the diagnosis and treatment of this condition.
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