To determine optimal conditions for allergen preservation, we investigated the influence of different stabilizing additives and of storage temperature on the allergen activity of apple protein preparations, obtained by extraction in phosphate buffer or by precipitation in diacetone alcohol and resolubilization in phosphate buffer in the presence or absence of enzyme inhibitors. For this purpose, the extracts were stored for 6 months either in frozen state at -20 degrees C or in lyophilized state at -20 degrees C, 4 degrees C, or room temperature and were characterized by SDS-PAGE, immunoblot, ELISA inhibition, and prick test. The highest stability revealed the extracts that were prepared by precipitation in the organic solvent in the presence of enzyme inhibitors, lyophilized, and stored at -20 degrees C. For storage of extract solutions at 4 degrees C, PBS/glycerol and cysteine/sodium citrate/glycerol were found to be the most effective stabilizing additives.
The aim of our investigation was to obtain a well-characterized active apple extract suitable for both in vivo and in vitro diagnostics by a technically simple method. For this purpose, apple extracts were prepared by homogenization in potassium phosphate buffer or by precipitation in organic solvents and resolubilization in potassium phosphate buffer in the presence or in the absence of enzyme inhibitors. These extracts were comparatively investigated by means of SDS-PAGE, two-dimensional electrophoresis, immunoblotting, RAST inhibition, and prick test. The in vitro investigations indicated that extracts prepared by precipitation in organic solvents (diacetone alcohol) at -20 degrees C have a higher allergen activity than those prepared by extraction in aqueous solutions. From the in vivo tests (prick test), it was concluded that application of inhibitors of cytoplasmic enzymes (phenol oxidases, peroxidases, proteases) already during extraction is an essential precondition for active prick test solutions. Correspondingly, the extract obtained by solvent precipitation in the presence of enzyme inhibitors appeared to be most suitable for clinical application.
This paper deals with the correlation of clinical scoring and serologic markers of inflammation in atopic dermatitis and psoriasis. Serum eosinophil cationic protein (ECP), soluble interleukin-2 receptor (sIL-2R), total serum IgE, IgG and IgM anti-IgE antibodies, and IgE immune complexes were evaluated in monitoring inflammatory skin diseases such as atopic dermatitis and psoriasis. Well-established clinical activity scores were used as standards in recording skin improvement under treatment in a clinical setting. Serum ECP was found to be increased in both atopic dermatitis and psoriasis patients compared to normal controls; sIL-2R and IgE immune complexes were increased only in atopics with increased serum IgE. Anti-IgE antibodies did not show any deviation in both groups of patients. There was a significant elevation of sIL-2R and IgE immune complexes and a nonsignificant elevation of ECP in high-IgE atopics in comparison to those with normal serum IgE. In both groups of patients, there was a significant reduction of ECP and sIL-2R accompanying the improving skin condition. Serum IgE and the other immune parameters failed to respond. In contrast to other studies, serum ECP failed to correspond significantly with disease activity in our study. Our results showed measurable changes of ECP and sIL-2R for atopic dermatitis and/or psoriasis under treatment, but comparison to clinical scores remains difficult due to the different basis of the two systems. The only significant correlation was established for relative changes in sIL-2R and psoriasis area and intensity (PASI), a correlation which might be a useful approach in psoriasis.
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