Enzymes as allergen: molecular and immunological studies

Abstract

The incidence of asthma and allergies has increased in many countries. As per estimates, 25% of the population worldwide suffers from allergic disorders including asthma (Valenta et al, 1999). Among the patients suffering with respiratory allergy symptoms, 20-30% are sensitized to fungal spores (Gioulekas et al., 2004). Allergic reactions progressively transform into regular diseases defined as allergic rhinitis, asthma, rhino-conjunctivitis, urticaria and eczema. The sensitization to fungi has been reported in the range of 5-30% in India (Bisht et al., 2003). Fungi such as Alternaria, Cladosporium, Aspergillus, Penicillium, Curvularia, Epicoccum, Fusarium, Mucor and Rhizopus have been recognized as important inhalant allergens at different places in the world. Biologic function of certain allergens from mites and fungi has been defined in previous studies (Bufe, 1998; Pomes, 2008a). However, enzyme (protease) as allergen was first reported in workers of detergent industry by Flindt (Flindt, 1969). In the last decade, few other enzymes have been reported as allergen and their mechanism of action was predicted (Pasquato et al., 2006.). Enzyme allergens explored in most of the studies are proteases, transferases, enolases, dehydrogenases and chitinases. But, they are required to be developed in bulk amount using recombinant DNA technology for in vitro and in vivo studies to elucidate their mechanism of action in the target tissue especially in airway disease. The enzyme like glutathione-S-transferase (GST) has antioxidant property but the allergenic nature restricts its use for therapeutic purpose. The variant of this enzyme may be of therapeutic value in airway inflammatory disorders. newline Oxidative stress is an important factor in the pathogenesis of asthma. Furthermore, antioxidant like GST is reduced in asthma patients. In the present study (Chapter 2), therapeutic effect of exogenous GST and mGST was evaluated in allergen induced mice model.