BACKGROUND: Grass pollen grains are important causes of respiratory allergies. The Philippines has a different grass flora compared to that of western countries, so pollen extracts have to be processed for use in the diagnosis and treatment of respiratory allergies. The local pollen extracts available in clinical practice have not yet been characterized, which is important in improving extract quality.
OBJECTIVE: This study aims to perform physicochemical characterization through protein content determination and gradient sodium-dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of extracts from four grasses: Cynodon dactylon (bermuda grass), Axonopus compressus (carabao grass), Imperata cylindrica (cogon), and Saccharum spontaneum (talahib) and immunologic characterization by identifying its IgE-binding component through immunoblot.
METHODS: This is a descriptive study. The pollen grains were processed into allergen extracts and protein contents were determined. The extracts were separated by gradient SDS-PAGE and subjected to immunoblotting. Bands were visualized using Fluorchem C2 aided with Alpha View Software.
RESULTS: Total protein in the pollen extracts ranged from 281.3-968.61 µg/ml. Protein bands of bermuda were in the 14.4-66.3 kDa range, carabao grass at 3.5-66.3 kDa, cogon at 3.5-200 kDA, and talahib at 21.5-66.3 kDa. A single IgE-binding protein band was seen on immunoblot at 55.4 kDa using a single serum sample.
CONCLUSION: Protein contents of the allergen extracts vary. The molecular weights of the different protein bands seem to correspond to known groups of grass pollen allergens. There was only one IgE-binding protein band seen on preliminary immunoblot.