Distinct epitope structures of defensin-like proteins linked to proline-rich regions give rise to differences in their allergenic activity.

BACKGROUND: Art v 1, Amb a 4, and Par h 1 are allergenic defensin-polyproline-linked proteins present in mugwort, ragweed, and feverfew pollen, respectively. We aimed to investigate the physicochemical and immunological features underlying the different allergenic capacities of those allergens. METHODS: Recombinant defensin-polyproline-linked proteins were expressed in E. coli and physicochemically characterized in detail regarding identity, secondary structure, and aggregation status. Allergenic activity was assessed by mediator releases assay, serum IgE reactivity, and IgE inhibition ELISA using sera of patients from Austria, Canada, and Korea. Endolysosomal protein degradation and T-cell cross-reactivity were studied in vitro. RESULTS: Despite variations in the proline-rich region, similar secondary structure elements were observed in the defensin-like domains. Seventy-four percent and 52% of the Austrian and Canadian patients reacted to all three allergens, while Korean patients were almost exclusively sensitized to Art v 1. This was reflected by IgE inhibition assays demonstrating high cross-reactivity for Austrian, medium for Canadian, and low for Korean sera. In a subgroup of patients, IgE reactivity toward structurally altered Amb a 4 and Par h 1 was not changed suggesting involvement of linear epitopes. Immunologically relevant endolysosomal stability of the defensin-like domain was limited to Art v 1 and no T-cell cross-reactivity with Art v 125-36 was observed. CONCLUSIONS: Despite structural similarity, different IgE-binding profiles and proteolytic processing impacted the allergenic capacity of defensin-polyproline-linked molecules. Based on the fact that Amb a 4 demonstrated distinct IgE-binding epitopes, we suggest inclusion in molecule-based allergy diagnosis.

Isolation and characterization of microcrystalline cellulose from oil palm biomass residue.

In this work, we successfully isolated microcrystalline cellulose (MCC) from oil palm empty fruit bunch (OPEFB) fiber-total chlorine free (TCF) pulp using acid hydrolysis method. TCF pulp bleaching carried out using an oxygen-ozone-hydrogen peroxide bleaching sequence. Fourier transform infrared (FT-IR) spectroscopy indicates that acid hydrolysis does not affect the chemical structure of the cellulosic fragments. The morphology of the hydrolyzed MCC was investigated using scanning electron microscopy (SEM), showing a compact structure and a rough surface. Furthermore, atomic force microscopy (AFM) image of the surface indicates the presence of spherical features. X-ray diffraction (XRD) shows that the MCC produced is a cellulose-I polymorph, with 87% crystallinity. The MCC obtained from OPEFB-pulp is shown to have a good thermal stability. The potential for a range of applications such as green nano biocomposites reinforced with this form of MCC and pharmaceutical tableting material is discussed.

Expression of lectin, interleukin-2 and histopathologic blood group binding sites in prostate cancer and its correlation with integrated optical density and syntactic structure analysis.

The binding of several biotinylated biologic probes was determined in sections of 20 surgical specimens of prostate cancer and of 21 biopsy specimens of hyperplastic prostate. Whereas neither the immunomodulatory, galactoside-specific lectin from Viscum album nor the human beta-galactoside-specific lectin (M(r) 14 kd) or its specific antibody discerned any remarkable differences, the lectin from Urtica dioica (UDA) and interleukin-2, the in vitro production of which is enhanced by this lectin, exhibited obvious preference for hyperplastic cells. In addition, the presence of binding sites for chemically synthesized blood group determinants was tested. Carcinoma cases revealed a higher percentage of binding of synthetic blood group trisaccharide H than hyperplasia cases. Due to these differences, diverse parameters, derived from measurement of integrated optical density (IOD) and from syntactic structure analysis, were correlated with the extent of binding of these biologic probes for the tumor cases. Primarily, parameters that are related to computation of a minimum spanning tree were significantly different in positive and negative cases for both UDA and interleukin-2. For the binding of blood group trisaccharide H the 5C exceeding rate, the 2CV deviation index and the distance of neighboring tumor cells with an IOD > 5 were clearly dissimilar. Our results thus suggest an extension of the panel of biologic probes for prostate cancer and substantiate the usefulness of correlations of binding of selected biologic probes to features derived from the assessment of IOD and syntactic structure analysis.