Biomedical subjects

A Vallverdú

Publications and source records attributed to A Vallverdú.

3 recordsLinked to original sources

PubMed1998

Characterization of recombinant Mercurialis annua major allergen Mer a 1 (profilin).

BACKGROUND: Two major allergens (Mer a 1A and Mer a 1B), tentatively identified as profilin, have been described in the euphorbiacea, Mercurialis annua. OBJECTIVES: We sought to clone and characterize these major allergens from M. annua pollen and to obtain the immunologically active and soluble recombinant allergen, which could then be used for diagnostic procedures and therapy. METHODS: Isolation of cDNA clones was performed by polymerase chain reaction amplification with degenerate primers. Expression in Escherichia coli BL21 (DE3) was carried out with a vector based in the T7 expression system, and the recombinant allergen was isolated by affinity chromatography on poly-(L-proline)-Sepharose. Electrophoretic (sodium dodecylsulfate-polyacrylamide gel electrophoresis, isoelectric focusing, and 2-dimensional polyacrylamide gel electrophoresis) and immunochemical methods (Western blot and ELISA) were used for the characterization of the recombinant allergen. RESULTS: Two cDNA inserts coding for M. annua pollen profilin (Mer a 1) were cloned and sequenced. Full-length Mer a 1 cDNA was expressed in E. coli as nonfusion protein. The final yield of recombinant Mer a 1 from the culture media after a single purification step on poly-(L-proline)-Sepharose was as much as 5 mg per liter. The reactivity of recombinant Mer a 1 with IgE antibodies present in sera from patients allergic to M. annua, Olea europaea, and Ricinus communis pollens was comparable to that of the natural counterparts, but latex profilin had no cross-reactivity with M. annua profilin. Recombinant Mer a 1 was shown to share B-epitopes with sunflower profilin. CONCLUSION: This approach is suitable for the production of defined and purified recombinant allergens, which could allow more detailed immunologic characterization of these proteins and the development of much more accurate diagnostic measures and specific anti-allergic treatments.

Allergens↗

PubMed1997

Mercurialis annua: characterization of main allergens and cross-reactivity with other species.

A multicentric study was conducted to evaluate the frequency of Mercurialis annua pollen sensitization in several areas of Spain and to select a population sample to characterize the main allergenic components in M. annua pollen. Patients were recruited from six hospitals in Spain. Out of 420 patients sensitized to pollens, 195 (46.4%) showed positive skin tests to M. annua, thus evidencing the high level of sensitization to the pollen of this plant in Spain. Thirty-seven sera with RAST class values to M. annua > or = 3 were selected for SDS-PAGE immunoblotting analysis. Two main allergenic components with molecular weights of 15.8 and 14.1 kD were detected in 59 and 51% of the sera, respectively, and they were identified as profilins. Isolation of the relevant allergens was made by affinity chromatography on a poly-L-proline-Sepharose column, followed by gel filtration and anion exchange chromatography in the micropreparative SMARTs System. A significant but low antigenic cross-reactivity between M. annua and Olea europaea, Fraxinus elatior, Ricinus communis, Salsola kali, Parietaria judaica and Artemisia vulgaris was demonstrated by several in vitro techniques.

Adolescent↗

PubMedDate not supplied

Allergens from Brazil nut: immunochemical characterization.

The increase in the consumption of tropical nuts in the Northern Hemisphere during the last years, has evolved in a simultaneous enhancement of allergic IgE mediated (Hypersensitivity type 1) reported cases produced by this kind of food. The Brazil nut is the seed of the Bertholletia excelsa tree (Family Lecythidaceae) and, as in other seeds, proteins represent one of its major components making up 15-17% of its fresh weight and 50% of defatted flour. Of these, storage proteins are the most important ones, and the 12 S globulin legumin-like protein and the 2 S albumin have been described as the most representative. The 2 S protein, due to its high sulfur-rich amino acid content (3% cysteine and 18% methionine), is being studied, cloned and expressed in some important agronomic seeds (soybean, bean, oilseed rape) in order to enrich the nutritional quality of them. The case of a patient with serious clinical allergic symptoms (vomiting, diarrhoea and loss of consciousness) caused by oral contact with the Brazil nut, is presented. The patient gave a positive Skin Prick Test response to Brazil nut, kiwi and hazelnut extracts, and negative to regionally specific aeroallergens and other food extracts. The patient serum showed a high level of specific IgE by RAST to Brazil nut (> 17.5 PRU/ml, Class 4), and significative levels to hazelnut, and mustard. In vitro immunological studies (SDS-Immunoblotting and IEF-Immunoblotting) revealed IgE-binding proteins present in the extract. It was shown that not only the heavy (Mr 9) and light (Mr 4) subunits of the known allergenic 2 S albumin but also the alpha-subunits (Mr approximately 33.5 and 32) and at least one of the beta-subunits (Mr approximately 21) of the 12 S Brazil nut globulin, hitherto never involved in allergic problems, showed a strong IgE-binding capacity.

Adolescent↗