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S Elsayed

Publications and source records attributed to S Elsayed.

At least 55 records · Page 3Linked to original sources
PubMed1990

Characterization of four major allergens of hen egg-white by IEF/SDS-PAGE combined with electrophoretic transfer and IgE-immunoautoradiography.

The antigenic and allergenic epitope maps of the hen egg-white ovalbumin, ovomucoid, ovotransferrin and lysozyme were obtained using one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis and two-dimensional sodium dodecyl sulfate gel electrophoresis following isoelectric focusing. The isoelectric points of egg-white proteins were assigned by the isoelectric focusing technique. Two-dimensional electrophoresis following isoelectric focusing provided further information regarding epitope mapping. Furthermore, electrophoretic transfer of the proteins to nitrocellulose and subsequent immunoautoradiography, clearly demonstrated the allergenicity of these proteins. An important benefit of these methods was confirming that lysozyme bound strongly to IgE in all the human sera from egg-allergic individuals and that lysozyme, in addition to ovalbumin, ovomucoid and ovotransferrin, was one of the major allergens of hen egg-white.

Allergens↗
PubMed1990

Seasonal variation of the conjunctival provocation test, total and specific IgE in children with birch pollen allergy.

In 20 children with birch pollinosis, conjunctival provocation tests (CPT) with a birch pollen preparation were performed and blood was drawn on five different occasions during 1 year. From November to February there was a decrease in the activity of the atopic disease as measured by CPT (p = 0.03), total serum IGE (p = 0.02) and birch pollen-specific serum IgE (not significant). Then all parameters increased until August (p less than 0.05). From August to November there was a decrease, significant for total IgE and birch-specific IgE (p less than 0.01). The correlation between CPT and the in vitro tests was poor. The conclusion is that the seasonal variations of CPT, total and specific IgE are similar but without close correlation between CPT and the antibody levels. The priming during the season is retained at least for 1 year.

Adolescent↗
PubMed1990

Purification and N-terminal amino acid sequence of two birch pollen isoallergens (Bet v I and Bet v II).

The major allergen of birch pollen BV45 (Bet v I) was previously isolated by molecular weight exclusion chromatography and eluted in the molecular weight region of 15-29 KD. Further purification of this fraction on an SP-Trisacryl M cation exchange matrix allowed 6 peaks of which which the 4th (BV4A4) and 6th (BV4A6) included two dominant IgE-binding birch pollen isoallergens designated Bet v I and Bet v II. Final purification, using the 'Applied Biosystems' Peptide Micro Separation System, revealed two sharp peaks with a high degree of homogeneity. This was ascertained by automatic N-terminal amino acid (AA) sequence analyses which showed high average repetitive yields of the phenyl-thiohydantoin (PTH) AAs of the isoallergens sequenced. N-terminal AA analyses of the two fractions allowed 51 cleavages with correct identifications of PTH AAs for 3 replicates. The sequence data of the two isoallergens showed large homologies with the hazel pollen allergen, Cor a I, the birch pollen allergen, Ag 23, and the translated cDNA sequence derived from cloning birch pollen allergen genes. The sequence homologies support that Betula verrucosa allergens were derived from a gene family expressing several isologous allergens, 2 of which with 13 variable residues in a segment of 51 AAs. The antigenicity of the two fractions, Bet v I and Bet v II, was demonstrated by fused rocket immunoelectrophoresis (FRIE) and by crossed immunoelectrophoresis (CIE) giving single symmetrical antigenic precipitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1989

[Anaphylactic shock during elective cesarean section. Sensitizing mechanisms and follow-up].

Anaphylactic reactions during anaesthesia are increasing. Women experience these reactions more often than men. In about 50% of the cases the reaction is due to a muscle relaxant drug. Recently, Australian and French researchers have described these reactions as possibly mediated by IgE in most of the patients. As regards Ig-antibody binding, the quaternary ammonium ions seem to be potential determinants in the muscle relaxant molecule. Patients may have been sensitized by exposure to cosmetics, disinfectants or solvents, and cross-reactivity between different neuromuscular blocking agents has been described earlier. We refer to a patient who experienced an anaphylactic shock during anaesthesia by suxamethonium. She was successfully treated with epinephrine, crystalloids and mechanical ventilation. We discuss peroperative treatment, further investigation, and management at later anaesthesiological procedures.

Anaphylaxis↗
PubMed1989

Common antigenic and allergenic determinants on codfish proteins detected with mouse monoclonal IgG and human IgE antibodies.

The antigenic and allergenic profiles of codfish extract have been examined and a comparison made of the specificities of the determinants defined by mouse monoclonal antibodies and human IgE antibodies. By gel electrophoresis, codfish extract was found to comprise a heterogeneous mixture of proteins, in which the principal component and allergen was Gad cI (allergen M). Using monoclonal antibodies and sera from human cod-allergic subjects as immunological probes, common antigenic and allergenic determinants were demonstrated on some codfish proteins. It was also established that, although two monoclonal antibodies recognized the same determinant on Gad cI, there was no cross-reactivity between this determinant and those specified by IgE antibodies in the sera of cod-allergic patients. The specificity of IgE populations directed against Gad cI was found to vary from patient to patient, and was indicative of the existence of two types of allergenic determinants: those unique to a particular allergen and those shared by other proteins in the extract. These studies promote speculation regarding the relative immunogenicity of antigenic and allergenic determinants and the size and diversity of the IgE repertoire, given the potential immunogenicity of the entire protein surface.

Allergens↗
PubMed1989

Dust from carpeted and smooth floors. I. Comparative measurements of antigenic and allergenic proteins in dust vacuumed from carpeted and non-carpeted classrooms in Norwegian schools.

Dust samples from fitted-carpets and linoleum floors in 12 schools in Norway were collected by vacuum cleaning. The presence of antigens and allergens of alder (Alnus incana), birch (Betula verrucosa), timothy (Phleum pratense), mould (Cladosporium herbarum), house dust mite (Dermatophagoides farinae), cat and dog dander, codfish, hen egg white and human dander were investigated by crossed immunoelectrophoresis (CIE), crossed radio-immunoelectrophoresis (CRIE) and radio-allergosorbent test (RAST) inhibition. No qualitative differences in allergen contents of dust from both types of floor tested were noted. Similarly, no relationship could be demonstrated between floor-type and allergen concentration under identical experimental conditions. Antigens and allergens of both cat and dog were frequently demonstrated in dust extracts. All extracts included human dander and mould allergens. In addition, most dust samples from both carpeted and smooth floors contained hen egg white and codfish allergens. Furthermore, the study demonstrated that dust from smooth floors and fitted-carpets was relatively free of mite and pollen from alder, birch and timothy.

Allergens↗
PubMed1989

Dust from carpeted and smooth floors. II. Antigenic and allergenic content of dust vacuumed from carpeted and smooth floors in schools under routine cleaning schedules.

Dust samples were collected twice from smooth and carpeted floors in 10 Norwegian schools. The content of antigens and allergens of alder (Alnus incana), birch (Betula verrucosa), timothy (Phleum pratense), cat and dog dander, house dust mite (Dermatophagoides farinae), mould (Cladosporium herbarum), hen egg white and codfish (DIII) were investigated by crossed immunoelectrophoresis (CIE), crossed radio immunoelectrophoresis (CRIE), radio allergosorbent test (RAST) inhibition and quantitative precipitation inhibition analysis by laser nephelometry. Antigens and allergens of cat and dog dander and hen egg white were most prevalent in the dust samples investigated. With the exception of hen egg white and codfish allergens, no statistically significant differences in mean allergen content were shown in identical quantities of freeze-dried dust extracts from carpeted and smooth floors. RAST-inhibition analyses of identical amounts of dust from either floors showed higher content of allergens of cat, dog, hen egg white, codfish, mould and timothy pollen in classrooms with carpets.

Allergens↗
PubMed1989

Synthetic allergenic epitopes from the amino-terminal regions of the major allergens of hazel and birch pollen.

Five immunogenic peptides from the major allergens of tree pollen extracts (residues 23-38) were synthesized by Merrifield solid-phase peptide synthesis. The primary structures of these peptides were deduced from the known N-terminal amino acid sequence of the major allergen of hazel, HIa, and birch, Bet v I. In a segment of 16 amino acids (23-38), 2 residues were the difference between birch and hazel. The selection of the peptides was on the basis of optimal hydropathicity. The segment 29-34 of these peptides was predicted to prefer a helical rather than beta-sheet conformational state. The insertion of amino acid residues during the synthesis was confirmed by the analysis of amino acid composition prior to coupling the preceding residue. The linearities of the synthetic chains were assigned by the primary structure analysis of the entire chain by automatic Edman degradation. The synthetic peptides were purified by gel filtration chromatography and reversed-phase high-performance liquid chromatography, resulting in satisfactory homogeneity of the preparations. The immunogenicity of the peptides was tested in rabbits using conjugated peptide-bovine serum albumin through a carbodiimide spacer arm. The results indicated that all constituents of the conjugate could elicit an immune response. The peptides gave precipitation lines in crossed immunoelectrophoresis when using rabbit antibodies against the conjugated preparation. All the synthetic peptides and analogues from region 23-38 could inhibit, in dose-response patterns, the binding of specific IgE to the intact molecules. Similar results were shown for the shorter segment 25-34, suggesting that the C-terminal tetrapeptide did not contribute to the activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1989

Reestimations of the protein concentrations of birch pollen allergen extracts selected as candidates for the international standard (IS) preparation.

The total protein concentrations of six selected candidates for an international standard (IS) of birch pollen were previously estimated (Ann Allergy 1987;58:71-77). The results of analyses showed large variations depending both on the method and the reference protein used. More than 2-fold variations in the protein content were obtained using Bradford's protein binding method. In the present communication the protein contents of these birch IS-candidates were reestimated by Lowry, a modified Lowry technique, Bradford's protein-dye binding, bicinchoninic acid reagent and amino acid compositions. Great variations were obtained for the protein contents, depending on the technique employed, emphasizing the difficulties of choosing a proper method of protein analyses of pollen allergens. The Lowry and the bicinchoninic acid reagent methods gave the highest obtained protein estimates, while the modified Lowry and Bradford's protein-dye binding methods showed the lowest values. The amino acid analysis gave concentrations similar to those obtained by Lowry and bicinchoninic acid reagent methods. The Lowry method seemed to be adequate for the analysis of plant proteins. The amino acid analysis is currently the most precise method for estimation of the protein concentration irrespective of additional prosthetic groups. A serious shortcoming of the method is that it requires an amino acid analyser or other liquid chromatrographic systems, which are not commonly in laboratory use.

Amino Acids↗
PubMed1988

Antigenic and allergenic determinants of ovalbumin. II. The reactivity of the NH2 terminal decapeptide.

The decapeptide 1-10 of hen's egg ovalbumin (OA), deduced from the known amino acid sequence (Gly-Ser-Ile-Gly-Ala-Ala-Ser-Met-Glu-Phe), was synthesized by Merrifield solid phase peptide synthesis with a yield of greater than 70%. The completeness of the insertion of amino acids during synthesis was monitored by the amino acid compositions of the peptide-resin, prior to coupling of the preceding residue. The linearity of the synthesis was supported by dansyl Edman degradation and detection of three NH2 terminal residues 5-dimethylamino-naphtheline-1-sulphonyl (DNS)-Gly, -Ser, -Ile, respectively. The peptide was purified by gel filtration chromatography and analytical reversed-phase high-performance liquid chromatography (HPLC). The homogeneity of the preparation was calculated both from the amino acid analysis and by integrating the peaks of HPLC to be greater than 83%. The antigenicity of the purified (P2) peptide could be detected by precipitation inhibition with the nephelometric technique. The decapeptide could also specifically react with functional structures on reaginic IgE molecule from the sera of individuals allergic to eggs, inhibiting its further binding to ovalbumin. An in-vivo experiment using direct skin test on two patients allergic to eggs showed no activity, rendering further testing unnecessary. The results suggest that the decapeptide of the NH2 terminal segment of OA encompasses an Ig-binding haptenic epitope.

Allergens↗
PubMed1988

Immuno-electronmicroscopic identification and localization of the antigenic proteins of tree pollen grains.

The localization of antigenic proteins on ultrathin sections of pollen grains represents an interesting approach to understanding the release mechanisms of these antigens when the pollen grains come in contact with various physiological fluids. Using different rabbit antibodies we have demonstrated the locations of these antigens in the various structures of pollen grains. We further demonstrated the cross-reactivities between alder (Alnus incana), birch (Betula verrucosa) and hazel (Corylus avellana) pollen allergens. Ultrathin sections of the pollen grains were prepared and allowed to react with two individually raised rabbit antibodies, (Ab-BV and Ab-ALK), against birch pollen. The sites of the Ag/Ab complex on the sections were labelled by protein A/gold, and identified in a transmission electron microscope. The two birch antibodies showed either quantitative or qualitative differences regarding their binding to various structures on the pollen sections. Using Ab-BV, the antigen-binding sites were located in the apertural region of the pollen grain and in the cytoplasm, while almost no gold labelling could be seen on the pollen surface. With the other antibodies (Ab-ALK), we could visualize the antigen-binding locations on the surface material of the pollen grains, particularly in the exine part of the wall and in the cytoplasm. A few gold particles could also be seen in the apertural region of the pollen. In hazel and alder pollen the exine part of the wall was the most densely labelled, whereas the cytoplasm and the aperture bound smaller numbers of gold particles. Cross-incubations: birch pollen incubated with antibodies against hazel (Ab-CA), or alder (Ab-AI), showed various intensities of gold labelling for each of the three species. Statistically, the differences in the number of gold particles bound per micron 2 grain section between birch, hazel and alder, were highly significant. The cross-reactivities between these antigens from the three pollen species were further tested using house-produced rabbit antisera against antigens of the three species by means of electrophoretic and autoradiographic techniques (CIE and CRIE). The three antibodies could precipitate the major IgE-binding antigen from all three pollen species.

Animals↗
PubMed1988

A comparison of the antigenic and allergenic components of birch and alder pollens in Scandinavia and Australia.

Allergens in birch (Betula) pollens from B. pendula grown in Australia and Norway, B. davurica and B. populofolia and from alder (Alnus incana) were identified by electroblotting, following separation by SDS-PAGE, transfer to nitrocellulose membranes and incubation with sera from birch pollen-allergic subjects. Of 42 antigenic components detected by protein staining in the pollen extract from B. pendula grown in Norway, 17 bound IgE. The allergenic components included those already reported in the literature at MWs of 40, 29, 25, 17 and 10-12 kd, as well as previously undescribed components at MWs of 90, 79, 60, 50, 38, 35, 31, 27, 23, 16, 15 and 14 kd. The major IgE-binding components were located in the low MW region 10-17 kd for all species of birch and alder pollen proteins studied. Results reported here provide the first evidence of birch and alder pollen allergies in Australia. Extensive heterogeneity was observed amongst the sera from birch pollen-allergic subjects in both Norway and Australia. Cross-reactivity appears to exist among the proteins present in pollen from the various birch species and from alder.

Australia↗
PubMed1988

Allergic response to birch and alder pollen allergens influenced by geographical location of allergic subjects.

A detailed analysis was made of the reactivity patterns of birch pollen-allergic subjects from Norway and Australia to the various IgE-binding components of pollens from several different birch and alder species. Typically, with each of the pollens examined, the Norwegian subjects exhibited a specific limited response pattern in which only a few of the 18 possible allergenic bands were recognized. A single, major IgE-binding band of approximate molecular weight 16-17 kD was recognized in each pollen by all the Norwegian patients used in the study. In contrast to this situation, there was no 'typical' recognition pattern amongst the Australian patients. Although recognition of the 16- to 17-kD components occurred in some cases, it was not dramatically superior to any other single component. Recognition of higher molecular weight components occurred more frequently than with the Norwegian group. Reasons for the differences in the response patterns of the Australian and Norwegian groups are discussed with reference to the exposure of the populations to different allergenic sources and genetic variation.

Allergens↗
PubMed1988

Comparative studies on tree pollen allergens. XIV. Characterization of the birch (Betula verrucosa) and hazel (Corylus avellana) pollen extracts by horizontal 2-D SDS-PAGE combined with electrophoretic transfer and IgE immunoautoradiography.

The crude aqueous extracts of birch (Betula verrucosa) and hazel (Corylus avellana) pollen were characterized by horizontal isoelectric focusing (IEF) and one-dimensional and two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis (1-D and 2-D SDS/PAGE). Isoelectric focusing reference patterns obtained in pH 3.5 to 9.5 gradient gels contained 31 and 41 bands while the 2-D patterns consisted of 51 and 72 protein spots, respectively. Electrophoretic transfer to nitrocellulose membranes and subsequent 125I-immunoautoradiography demonstrated IgE binding in the region between pH 4.8 and 5.4 for both extracts. The main allergenic reactivities of this pH region were distributed by SDS/PAGE to the molecular weights of 29.5, 17, and 12.5 kilodaltons for birch and 15.5 and 12 kilodaltons for hazel. The high resolving power and the independence of rabbit antibodies were considered the major advantages of the described 2-D methodology as compared with conventional crossed immunoelectrophoretic and radioimmunoelectrophoretic techniques.

Animals↗
PubMed1987

Comparative studies on tree pollen allergens. XVII. Immunochemical analysis of the international standardization extracts of birch (Betula verrucosa) pollen as compared with a local partially purified extract.

Six different birch pollen extracts were analyzed by 20 laboratories for the standardization of birch (Betula verrucosa) pollen extracts used for diagnosis and specific therapy of patients with birch pollen allergy. The extracts were collected and delivered by the International Union of Immunological Societies, Allergen Standardization Subcommittee. One of the extracts, designated M, was proposed as an international standard (IS)-candidate of birch pollen extracts. The protein content of the IS candidate M was found to be 1.12 mg/mL, more than 2-fold higher than any of the other extracts analyzed. This preparation was among the extracts containing the highest number of protein components, as shown by isoelectric focusing, 28 lines, and by 11 precipitates in crossed immunoelectrophoresis. The allergenic reactivities were tested by crossed radioimmunoelectrophoresis (CRIE) and by radioallergosorbent test (RAST)-inhibition. In CRIE, the proposed IS (M) showed similar affinity for binding patients' IgE as the other extracts, as judged by the autoradiographic illustrations. Except for extract L, the values of RAST-inhibition for the rest were very similar. An IS extract should qualify for the criteria suggested for an optimal allergen preparation, containing minimal amounts of non-allergenic antigens and providing quantitatively and qualitatively all the allergenic proteins. The appropriateness of this selection seems unjustified in view of the above criteria.

Allergens↗