Fusarium solani major allergen peptide IV-1 binds IgE but does not release histamine

Spectrum of Allergens and Allergen Biology in India

The growing prevalence of allergy and asthma in India has become a major health concern with symptoms ranging from mild rhinitis to severe asthma and even life-threatening anaphylaxis. The "allergen repertoire" of this subcontinent is highly diverse due to the varied climate, flora, and food habits. The proper identification, purification, and molecular characterization of allergy-eliciting molecules are essential in order to facilitate an accurate diagnosis and to design immunotherapeutic vaccines. Although several reports on prevalent allergens are available, most of these studies were based on preliminary detection and identification of the allergens. Only a few of these allergen molecules have been characterized by recombinant technology and structural biology. The present review first describes the composition, distribution pattern, and natural sources of the predominant allergens in India along with the prevalence of sensitization to these allergens across the country. We go on to present a comprehensive report on the biochemical, immunological, and molecular information on the allergens reported so far from India. The review also covers the studies on allergy- related biosafety assessment of transgenic plants. Finally, we discuss the allergen-specific immunotherapy trials performed in India.

Allergens from Fusarium solani identified by immunoblotting in asthma patients In Iran

We extracted Fusarium solani antigens to evaluate specific anti-F. solani IgE in fifty-one patients with asthma (33 men and 18 women) and in 22 non-atopic healthy subjects (15 men and 7 women). F. solani strains were cultured in Sabouraud glucose agar and subjected to cell disruption using the freeze-and-thaw method. The obtained cytoplasmic extracts were analysed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Sensitisation to F. solani antigens has been evaluated in asthmatic patients using the immunoblotting assay. The SDS-PAGE identified 29 protein bands in the cytoplasmic extracts of F. solani isolates, with molecular weights ranging from 24 kDa to 112 kDa. Immunoblotting detected specific anti-F. solani IgE antibody in all asthma patients, but not in the control group. The predominant reactive allergens in patients corresponded to the bands with molecular weights of 24 kDa, 58.5 kDa, 64.5 kDa, 69 kDa, 72 kDa, and 97 kDa. Our results suggest that various allergenic components of F. solani may produce symptoms of asthma in susceptible individuals and they call for further research.

Epi p 1, an allergenic glycoprotein ofEpicoccum purpurascensis a serine protease

Epicoccum purpurascens (EP) is a ubiquitous saprophytic mould, the inhalant spores and mycelia of which are responsible for respiratory allergic disorders in 5-7% of population worldwide. The diagnosis/therapy of these disorders caused by fungi involves the use of standardized and purified fungal extracts. A 33.5 kDa glycoprotein, Epi p 1 released histamine from whole blood cells of EP allergic patients at a concentration of 50-ng protein. The high specific IgE values detected in EP hypersensitive sera indicated that Epi p 1 is capable of mediating type I hypersensitive reaction in predisposed individuals. It also showed protease activity by virtue of its dose dependent cleavage of serine protease specific synthetic substrate, N-benzoyl arginine ethyl ester hydrochloride (BAEE). The serine protease nature of Epi p 1 was confirmed by its N-terminal sequence (ADG/FIVAVELD/STY) homology to a subtilisin like serine protease. The protease activity of Epi p 1 may be responsible for making its way into the system of pre-disposed individuals through epithelial cell detachment and the histamine releasing ability by cross-linking of IgE antibodies on cell surface is the cause of its allergenic nature.

Detection of Mercury and Other Undetermined Materials in Skin Biopsies of Endemic Pemphigus Foliaceus

A novel variant of endemic pemphigus foliaceus (EPF) was described among individuals in an area surrounding El Bagre, Colombia, South America. The population in this rural mining community is exposed to high environmental levels of mercury, used for gold extraction, as well as other minerals, metalloids, and trace elements (e.g., quartz, rutile, granite, magnetite, and almenite) and ultraviolet radiation. Fifty control subjects and fifty EPF patients in the endemic area were examined for the presence of mercury in skin biopsies and hair, using autometallographic and mass spectroscopic analyses, respectively. Simultaneously, serum levels of IgE were measured, and cutaneous tests for hypersensitivity reactions were performed. Using autometallography, mercuric sulfides/selenides were detected in 14 of 51 skin biopsies distributed similarly in the control and patient groups. However, significantly higher serum IgE levels and mercury concentrations in hair, urine, and nails were found in patients compared with controls. Microscopic analysis revealed mercuric sulfides/selenides concentrated within and around the sweat gland epithelium, as well as in dendritic cells. Five skin biopsies from EPF patients and five from controls that tested positive for the presence of mercuric sulfides/selenides by autometallography were randomly selected for electron microscopic analysis. This analysis revealed a mixed electron-dense and electron-light material closely associated with desmosomes in patients. However, there were intracellular vesicles containing an amalgam of electron-dense and electron-light materials only in the EPF patients. Thus, EPF-affected individuals are exposed to high levels of environmental mercuric sulfides/selenides and other elements. This is the first study reporting mercuric sulfides/selenides in skin biopsies from people living in a focus of EPF, and these compounds may play a role in the pathogenesis of autoimmunity.

Purification and characterization of a cross-reactive 45-kD major allergen of Fusarium solani

BACKGROUND

Fusarium solani (FS) is an important source of fungal allergen. A 45-kD major allergen of FS showed reactivity with patients' sera sensitive to many fungi.

OBJECTIVES

To purify and characterize a 45-kD common allergenic protein from FS, which may be useful for the diagnosis of and therapy for fungal allergy.

METHODS

FS culture filtrate extract was seperated on SDS-PAGE; 45-kD protein was electroeluted and purified on C18 column using reverse-phase high-pressure liquid chromatography (rpHPLC). The purified protein was functionally and biochemically characterized by in vitro and in vivo methods.

RESULTS

The 45-kD protein showed a single peak on rpHPLC. The N-terminal amino acid sequence of this protein did not show homology to enolase or known fungal proteins. It showed cross-reactivity with Epicoccum nigrum, Curvularia lunata, Cladosporium herbarum and Alternaria alternata by ELISA and ELISA inhibition using rabbit antibodies raised against these fungi. IgE ELISA inhibition with patients' sera positive to different fungi demonstrated allergenic cross-reactivity of the 45-kD protein with other fungal extracts. This 45-kD protein released a significant amount of histamine in FS-allergenic patients.

CONCLUSION

A cross-reactive 45-kD allergenic/antigenic protein was purified to homogeneity and characterized. It has prospects for use in allergen therapy.