Monoclonal antibodies against whole body extract of the dust mite Blomia tropicalis

RESUMO

OBJECTIVE: To produce and characterize monoclonal antibodies (mAbs) against whole body extract of the dust mite Blomia tropicalis (Bt). BACKGROUND: Bt is an important source of allergens causing allergic diseases in tropical and subtropical regions. mAbs are excellent tools for delineating cross-reactivity between Bt and other mites. MATERIALS AND METHODS: Mice were immunized with extracts of Bt. mAbs were produced by standard techniques. Hybridoma screening was performed by ELISA. Ascitic fluids were produced and partially purified by adsorption chromatography. Reactivity of mAbs against extracts of Bt and Dermatophagoides pteronyssinus (Dp) was analyzed by ELISA, immunoblots and ELISA inhibition. Also, reactivity of mAbs against the putative cysteine protease rBlo t 1 from Bt was tested. RESULTS: Three IgG mAbs were obtained and partially purified. The mAbs reacted with Bt by ELISA. In immunoblots, mAbs recognized two protein components of 29 and 35 KD. Also, the mAbs reacted with Dp extracts by ELISA, and the same sized components were detected in immunoblots. In competitive ELISA, Dp extract reduced in 62% the reactivity with Bt antigens, and Bt extract produced a maximum reduction of reactivity against Dp antigens of 83%. The mAbs recognized rBlo t1. The homology between Blo t1 and the proteins recognized by the mAbs was high (90%) as the inhibition assays demonstrated. CONCLUSIONS: The cross-reactivity between Dp and Bp could be related with the presence of proteins as their respective cysteine proteases. The produced mAbs have proven to facilitate the identification of antigens of Bt and to determine the possible cross-reactivity between Bt and other common mites of the acarofauna of tropical and subtropical countries where Bt is commonly found.