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Les albumines

dimanche 15 juin 2008, par Allerdata


Les albumines sont les protéines principales du sérum. Elles sont formées de 3 domaines dont 2 présentent une cavité hydrophobe permettant le transport de molécules peu hydrosolubles .

Leur masse est d’environ 67 kDa.

Du fait de la vascularisation ou des mécanismes de secrétions glandulaires, on retrouve de l’albumine dans les muscles, dans les secrétions sébacées (mammifères) ou uropygiales (oiseaux), dans le lait, et divers organes (abats).

Les œufs des oiseaux contiennent aussi des albumines dans le jaune : elles portent un nom différent (livétines) bien qu’étant identiques aux albumines sériques du volatile d’origine.

Plusieurs protéines ont un nom faisant penser aux albumines mais n’en sont pas du tout sur le plan des familles de protéines :

  • Les parvalbumines (poissons),
  • l’ovalbumine et la conalbumine (blanc d’œuf),
  • la lactalbumine (lait),
  • les 2 S-albumines (protéines de stockage des graines),
  • les préalbumines (certaines lipocalines des phanères de mammifères).

Les albumines sont responsables de diverses associations allergiques, dont le syndrome porc-chat et le syndrome œuf-oiseaux (cf. Viandes, cf. œufs et oiseaux).

Des réactions allergiques per-opératoires sont exceptionnellement dues aux albumines (moins de 1% des cas du GERAP ).
Il a aussi été décrit une allergie respiratoire professionnelle à l’albumine .

Plus généralement, elles peuvent contribuer à des réactions croisées entre viande, lait et phanères, ou dans le cas des volailles entre viande, œuf et plumes.

Ces réactivités croisées sont dépendantes :

  • du degré d’homologie entre les albumines concernées.
    • La figure ci-dessous donne les pourcentages d’identité entre diverses albumines.
    • Elle montre que l’albumine bovine est très proche de l’albumine ovine et que les albumines de mammifères croiseront difficilement avec les albumines aviaires .
    • Une bonne homologie au niveau d’épitopes B est importante aussi, rendant moins directe la relation pourcentage d’identité globale /relativité croisée .

  • Du degré de modification des protéines sous l’effet de la chaleur dans le cas d’un aliment cuit.
    • La réactivité croisée des épitopes qui existait à l’état natif peut être abolie par modification des épitopes lors de la cuisson.
    • Ceci est net pour les viandes, une allergie étant vue chez des patients sauf si la viande est très intimement cuite.

Les albumines ont une allergénicité inférieure à d’autres allergènes de mammifères si l’on se base sur la prévalence de leur positivité :

  • en général les albumines des phanères de chat, chien, cheval, etc.… sont positives chez 20-40 % des patients . Cela résulte peut-être de la relative proximité de ces albumines vis-à-vis de l’albumine humaine (cf. graphiques ci-dessus) .
  • Pour le chat, l’albumine serait dominante chez moins de 2 % des sujets et, en cas d’allergie au chat, la réactivité pour l’albumine serait toujours accompagnée d’une réactivité pour d’autres allergènes (ex. Fel d 1) .
  • Dans le cas des oiseaux, les albumines jouent un rôle plus net, notamment dans le cas du jaune d’œuf. Ceci étant, il est très rare de rencontrer une allergie à l’œuf où la réactivité au jaune soit sans réactivité au blanc.

De nombreux travaux ont montré une large réactivité croisée entre albumines de mammifères : entre chat et chien, entre rat et souris, entre chat ou chien et cobaye ou cheval ou bœuf, etc...

Ces réactivités croisées ne sont cependant pas systématiques. par exemple :

  • parmi des patients allergiques au cheval il a été trouvé : 39% de sujets positifs pour l’albumine de chien ou de chat, 16% pour celle du cheval, 12% pour le bœuf, 9% pour le rat et le lapin, 2% pour le porc et le poulet
  • parmi des patients avec un TC positif pour le chat et positifs en CAP pour le chien et le cheval (41%), il était noté 83% de sujets positifs pour une albumine au moins : 21% positifs pour les 3 albumines (chat, chien, cheval), 17% pour 2 et 44% pour une seule. Une meilleure homologie chat-chien était retrouvée dans ces répartitions plutôt que chat-cheval
  • parmi 60 patients allergiques à divers animaux et présentant une réactivité pour les albumines, celle-ci était relevée chez 85% pour chat et/ou chien, 75% pour le cobaye, 70% pour le cheval, 60% pour le lapin et le hamster, 50% pour le porc, le mouton, la souris ou le rat, mais seulement 20% pour le bœuf. A noter : 20% pour l’albumine de poulet et 1 patient pour celle de pigeon

Ces écarts de réactivité croisée montrent que certains épitopes d’albumines sont spécifiques de telle ou telle espèce .

Le niveau d’atopie joue sur cette réactivité croisée et des patients allergiques au chat et au chien présentent plus souvent des TC positifs pour d’autres mammifères que des patients allergiques au chat mais pas au chien  :

Tests cutanés positifsChevalBoeufLapinPorcCobaye
Allergiques au chat (n=6) 3 2 1 0 2
Allergiques au chat et au chien (n=10) 7 6 4 4 3

La barrière mammifères / oiseaux concernant la réactivité croisée des albumines n’est pas absolue : en plus de réactivités sériques déjà notées plus haut, Spitzauer avait noté que l’albumine de poulet pouvait donner une réponse positive avec un test cellaire (libération d’histamine) chez un patient allergique au chien .

Et, dernièrement, chez une patiente présentant une allergie respiratoire au porc et au chat ainsi qu’une allergie alimentaire au poulet, il a pu être montré une réaction croisée entre albumine de chat et albumine de poulet . Chez cette patiente, l’hémoglobine de porc semblait participer également au tableau clinique.

[1] - Pilette C, Sohy C, Sauvage C, Just N, Wallaert B. L'allergie aux albumines sériques. Rev Fr Allergol Immunol Clin 2003;43:180-185
L'allergie à l'albumine sérique d'origine animale est une affection fréquente, nettement sous-diagnostiquée actuellement. Les voies de sensibilisation à cette protéine sont multiples étant donnée sa présence ubiquitaire dans les fluides biologiques. L'allergie à l'albumine contenue dans la viande de boeuf est la plus souvent rapportée et est fréquemment croisée avec les autres viandes. Les manifestations cliniques sont variées : diarrhée récurrente, dermatite atopique, syndrome oral, voire angio-oedème ou choc anaphylactique. L'albumine contenue dans les phanères des chats ou des chiens peut être responsable d'une rhinite ou d'un asthme. Les allergies croisées sont fréquentes, comme le classique syndrome porc-chat, mais aussi entre les oeufs et le lait ou les volailles. Le diagnostic est confirmé par tests épicutanés avec l'albumine pure et/ou par la recherche d'anticorps IgE spécifiques. Selon la symptomatologie, le traitement pourra consister en la cuisson attentive des aliments, l'éviction des contacts avec les chats ou les chiens ou en un traitement symptomatique.
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[2] - Mertes PM, Malinovsky JM, Alla F, Studnicska D, Tréchot P, Laxenaire MC. Epidémiologie des réactions d'hypersensibilité immédiates peranesthésiques chez l'adulte et l'enfant: bilan de 8 années du Gerap. Rev Fr Allergol Immunol Clin 2008;48:217-221
Les réactions d‚hypersensibilité immédiate, qu‚elles soient médiée par les immunoglobulines E (HSI IgE) ou non (HSI non IgE) survenant au cours de l‚anesthésie demeurent un sujet de préoccupation majeure. Les auteurs rapportent les données de huit années de surveillance épidémiologique effectuée par le Gerap. Deux mille cinq cent seize patients ayant présenté une réaction clinique évocatrice d‚une hypersensibilité immédiate entre le 1er janvier 1997 et le 31 décembre 2004 ont été inclus dans l‚étude. Une réaction non IgE-médiée a été diagnostiquée dans 700 cas (27,82 %), un diagnostic de réaction à médiation IgE ayant été retenu dans 1816 cas (72,18 %). Les agents plus fréquemment incriminés étaient les curares (n =1067, 58,08 %), suivi du latex (n =361, 19,65 %) et des antibiotiques (n =236, 12,85 %). Chez l‚enfant, les résultats étaient significativement différents. Le latex étant impliqué dans plus de 50 % des cas, suivi des curares (39 %) et des antibiotiques (10,2 %). Chez l‚adulte, les résultats confirment l‚existence d‚une prédominance féminine, quelque soit le mécanisme de la réaction, cette prédominance n‚est pas retrouvée chez l‚enfant. Ces résultats confirment la nécessité d‚un bilan systématique en cas de survenue d‚une réaction d‚hypersensibilité immédiate survenant au cours de l‚anesthésie et l‚intérêt du développement de centres de consultation spécialisé en allergo-anesthésie capables d‚apporter une aide aux anesthésistes et aux allergologues.
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[3] - Joliat TL, Weber RW. Occupational asthma and rhinoconjunctivitis from inhalation of crystalline bovine serum albumin powder. Ann Allergy 1991;66:301-304
A 24-year-old white female laboratory technician developed recurrent rhinoconjunctivitis and wheezing immediately following repeated exposure to purified lyophilized bovine serum albumin (BSA). Prick and titrated intradermal skin tests revealed strongly positive results in the patient and negative results in normal controls. A titrated double-blind, placebo-controlled bronchial inhalation challenge with an aqueous BSA solution was positive at 10 mg/mL. Use of an albuterol metered dose inhaler and avoidance of laboratory exposure to BSA have resulted in resolution of symptoms. These results are consistent with an IgE-mediated mechanism, and this case represents the first reported instance of occupational asthma and rhinoconjunctivitis to inhaled BSA powder.
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[4] - Aalberse RC, Stapel SO. Structure of food allergens in relation to allergenicity. Pediatr Allergy Immunol 2001;12(suppl. 14):10-14
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[5] - Restani P, Beretta B, Fiocchi A, Ballabio C, Galli CL. Cross-reactivity between mammalian proteins. Ann Allergy Asthma Immunol 2002;89(6 Suppl. 1):11-15
BACKGROUND: Cross-reactivity between food allergens occurs when they share part of their amino acid sequence, or when their three-dimensional molecular structure causes them to have a similar capacity to bind specific antibodies. OBJECTIVES: To review data from our laboratory on cross-reactivity between mammalian proteins (milk and meat allergens). METHODS: Studies used immunoelectrophoresis (sodium dodecyl sulfate-polyacrylamide gel electrophoresis/polyacrylamide gel electrophoresis and immunoblotting), and animal monoclonal antibodies. RESULTS: The findings suggest that animal monoclonal antibodies specific for cow's milk proteins are able to recognize the major part of milk proteins from mammals bred in Mediterranean countries (sheep, goat, and buffalo); weak cross-reactivity was observed with milk proteins from mares and donkeys. None of the antibodies used in our studies reacted with proteins from an exotic mammalian species: the camel. Similar cross-reactions were found with human circulating immunoglobulin E from children allergic to milk. With regard to beef allergy, monoclonal antibodies specific for bovine serum albumin cross-reacted only with ovine serum albumin, whereas the number of sera from allergic children able to recognize other mammalian serum albumins depended directly on the closeness of phylogenetic relationship between animal species and inversely on the percent identity with human serum albumin in the main epitopic sequence. CONCLUSION: An area of heterogeneity between animal and human species in a critical amino acid sequence (epitope) of an allergen can determine the degree of immunogenic activity.
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[6] - Restani P, Ballabio C, Cattaneo A, Isoardi P, Terracciano L, Fiocchi A. Characterization of bovine serum albumin epitopes and their role in allergic reactions. Allergy 2004;59(Suppl. 78):21-24
OBJECTIVE: This review provides updated information on conformational and sequential epitopes identified in bovine serum albumin (BSA) and summarizes available data about the role of structural modifications on BSA antigenicity/allergenicity. DATA SOURCES: Data on beef allergy and BSA antigenicity are reported, with reference both to the basic literature and to clinical results obtained by our group. RESULTS AND DISCUSSION: BSA is an important allergen involved in milk and beef allergy. The presence of conformational epitopes has been suggested by indirect evidence, while at least one sequential epitope has been experimentally identified. The role of structural modifications on BSA antigenicity is discussed as well as the increased tolerance observed in allergic subjects consuming beef as strained (homogenized) and freeze-dried derivatives . CONCLUSION: Study of the molecular characteristics of a known major allergen allows the identification of technological processes that may be capable of improving the tolerance of allergic subjects to a specific food. Even though any hoped for reduced allergenicity must be verified under medical supervision, the use of new products could obviate the need to avoid important foods such as meat in childhood.
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[7] - Rancé F, Juchet A, Brémont F, Dutau G. Correlations between skin prick tests using commercial extracts and fresh foods, specific IgE, and food challenges. Allergy 1997;52:1031-1035
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[8] - Virtanen T, Kinnunen T. Mammalian allergens. In Lockey RF. and Ledford DK, (eds). Allergens and Allergen Immunotherapy for Allergic Diseases. 4th ed. 2008, New York: Informa Healthcare USA, Inc., p. 201-18
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[9] - Spitzauer S, Pandjaitan B, Muhl S, Ebner C, Kraft D, Valenta R, et al. Major cat and dog allergens share IgE epitopes. J Allergy Clin Immunol 1997;99:100-106
Patients allergic to cats and dogs frequently display IgE reactivity against allergens from different animals, suggesting a cross-sensitization to common allergenic determinants. Although albumins have been recognized as relevant cross-reactive allergens, little is known regarding cross-reactive epitopes of the major cat and dog allergens. OBJECTIVE: In this study, sera from patients allergic to cats and/or dogs were used to investigate the presence of common IgE epitopes among the major cat and dog allergens. METHODS: The IgE reactivity profile of 109 patients who were allergic to allergens from several species of animals was determined with nitrocellulose-blotted cat and dog allergens. Sera from patients who were strongly allergic to the major cat and dog allergens were tested for the presence of cross-reactive IgE antibodies by one-dimensional and two-dimensional immunoblot inhibition experiments and by quantitative measurements obtained with the CAP-FEIA system (Pharmacia). RESULTS: Sixty-eight of 109 patients with animal allergy showed IgE reactivity to cat allergens and dog allergens. Sera from patients with both cat and dog allergy detected allergens of similar molecular weight in nitrocellulose-blotted cat and dog hair/dander extracts. Common, as well as species-restricted, IgE epitopes of the major cat and dog allergens could be demonstrated by IgE inhibition studies. CONCLUSION: Shared IgE epitopes of the major cat and dog allergens may provide an explanation for the clinical observation that allergies to cats and dogs are frequently associated.
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[10] - Blanc A, Donnay C, Metz-Favre C, Kopferschmitt-Kubler MC, de Blay F, Pauli G. Rôle de l'albumine sérique en tant qu'allergène croisant entre les mammifères. Rev Fr Allergol Immunol Clin 2006;46:361-362
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[11] - Spitzauer S, Pandjaitan B, Soregi G, Muhl S, Ebner C, Kraft D, et al. IgE cross-reactivities against albumins in patients allergic to animals. J Allergy Clin Immunol 1995;96:951-959
Type I allergic symptoms and severe asthma in particular are frequently caused by animal hair/dander proteins, among which albumins are possible cross-sensitizing allergenic components. METHODS: The significance and degree of IgE-cross-reactivities against various albumins were studied in a representative number (n = 200) of patients allergic to animals with hair/dander extracts, purified albumins from different animals, and a recombinant dog albumin fragment expressed in lysogenic Escherichia coli Y1089 and purified as a beta-galactosidase fusion protein. RESULTS: Despite a high degree of sequence homology among different albumins, a remarkable variability of IgE cross-reactivities was observed, indicating that some patients were sensitized preferentially against certain albumins. Most of the patients allergic to albumins, however, reacted to dog, cat, and horse albumin, which also bound a high percentage of albumin-specific IgE. CONCLUSION: The purified recombinant dog albumin fragment, representing 265 amino acids of the mature protein, bound IgE from all 15 patients allergic to albumin tested suggesting its potential usefulness for diagnosis and perhaps therapy.
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[12] - Spitzauer S, Schweiger C, Sperr WR, Pandjaitan B, Valent P, Muhl S, et al. Molecular characterization of dog albumin as a cross-reactive allergen. J Allergy Clin Immunol 1994;93:614-627
Indoor allergens comprise a group of allergenic proteins that are commonly derived from house dust mite and cat and dog dander. In addition to the two major dog allergens (molecular weights: 19 and 23 kd), dog albumin represents an important allergen for up to 35% of patients who are allergic to dogs. In IgE immunoblot inhibition studies and histamine release tests it has been demonstrated that patients who react to dog albumin exhibit IgE reactivity with purified albumins from cat, mouse, chicken, and rat. The proportion of dog-specific IgE directed against dog albumin was determined for patients allergic to dog albumin, and it ranges from 70% to 90%. By IgE immunoscreening of a lambda gt11 expression library from a dog salivary gland, we identified a number of reactive complementary DNA clones. All patients with IgE reactivity against natural dog albumin displayed IgE reactivity to the beta-galactosidase fusion protein encoded by clone 54c, which was therefore assumed to contain major IgE epitopes of dog albumin. The deduced amino acid sequence of clone 54c was compared with the Swiss-Prot library, and significant sequence homologies were found with albumins from different species (human: 82.6%, pig: 81.8%, cattle: 77.3%, sheep: 78.8%, mouse: 75.8%, and rat: 76.2%). Several other IgE-positive clones hybridized with oligonucleotides that were prepared according to this sequence. Partial complementary DNA coding for dog albumin fragments may be considered a useful tool for further characterization of major IgE epitopes of dog albumin.
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[13] - Wood RA. Laboratory animal allergens. ILAR J 2001;42:12-16
Comment in: ILAR J. 2001;42(1):1-3 Allergic sensitivity to laboratory animals can pose a significant occupational hazard to anyone with regular animal contact. Reactions to mice and rats are most common although all furred animals produce allergens that can lead to sensitization and disease. Most of the relevant allergens of laboratory animals have been defined and characterized, which has revealed that these allergens are typically small, acidic glycoproteins and that many of them are members of a superfamily of extracellular proteins called lipocalins. In addition to understanding their molecular characteristics, the identification of these allergens has also made it possible to measure their distribution in laboratory environments and to relate exposure levels to sensitization and symptoms. These studies have shown that the major laboratory animal allergens are carried on small particles that are both capable of remaining airborne for extended periods and penetrating into the lower airways of exposed workers. These advances in the understanding of these important occupational allergens will allow for the development of better methods of diagnosis and avoidance for affected workers and others who may be at risk for future difficulties. [References: 49]
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[14] - Aalberse RC. Structural features of allergenic molecules. Chem Immunol Allergy 2006;91:134-146
In this paper the relation between protein allergenicity (the capacity to induce IgE antibody production or the capacity to activate mast cells sensitized with IgE antibodies induced by a cross-reactive allergen) and protein structure is discussed. While cross-reactivity is to a large degree predictable from primary sequence comparisons, the IgE-inducing capacity is mostly determined by factors other than the primary sequence. Two routes to IgE are discussed: (1) the atopic route (used by allergens from pollen and mites) in which a direct switch from mu to epsilon is common and (2) the 'modified Th2' route (used by allergens from pets) in which the class switch to IgE is often preceded by a switch to IgG4. According to this working hypothesis, the choice between these two routes is determined at the level of the germinal center activity.
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[15] - van Ree R, Van Leeuwen WA, Bulder I, Bond J, Aalberse RC. Purified natural and recombinant Fel d 1 and cat albumin in in vitro diagnostics for cat allergy. J Allergy Clin Immunol 1999;104:1223-1230
Current diagnostics and therapeutics for cat allergy are based on cat epithelial extracts originating from highly variable source materials. This gives rise to several problems: variability of allergen composition, contamination with house dust mite allergens, and potential transfer of pathogenic agents. OBJECTIVE: The aim of this study was to investigate the feasibility of replacing cat epithelial extracts with purified natural or recombinant allergens. METHODS: Sera (n = 509) were selected on the basis of a positive cat RAST result and tested in a RAST for IgE reactivity to purified Fel d 1, cat albumin (CA), or both. The analysis was performed with both natural and recombinant allergens. In addition, some sera were further analyzed by means of immunoblotting. A serum pool was used for cat RAST inhibition with purified natural and recombinant allergens as inhibitors. RESULTS: Natural and recombinant Fel d 1 caused very similar results: 94.1% and 96.1% positive test results, respectively. In general, the negative sera were low responders to cat extract. The addition of CA (16.7% positive sera) resulted in a decrease in the number of discrepencies between purified allergens and whole extract to 2.8%. Only for 2% of all sera, sensitization to cat was largely explained by IgE reactivity to CA. IgE reactivity to Fel d 1 accounts for 88% of the total IgE response to cat allergens, as was demonstrated by RAST, with Fel d 1 concentrations nearing saturation. Recombinant Fel d 1 performed equally well in the RAST analysis. Recombinant CA was succesfully expressed in the yeast Pichia pastoris, and its immune reactivity closely resembled that of its natural counterpart. CONCLUSION: Natural and recombinant Fel d 1 and CA are good candidates for replacing ill-defined cat dander extracts in diagnostics for cat allergy. Although CA is not essential for the vast majority of cat-sensitized patients, some subjects are selectively sensitized to this serum protein.
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[16] - Blanc A, Donnay C, Metz-Favre C, Kopferschmitt-Kubler MC, de Blay F, Pauli G. Rôle de l'albumine sérique en tant qu'allergène croisant entre les mammifères. Rev Fr Allergol Immunol Clin 2006;46:361-362
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[17] - Goubran Botros H, Grégoire C, Rabillon J, David B, Dandeu JP. Cross-antigenicity of horse serum albumin with dog and cat albumins: study of three short peptides with significant inhibitory activity towards specific human IgE and IgG antibodies. Immunology 1996;88:340-347
Horse serum albumin is present in the near vicinity of the animal, while dog and cat serum albumins are very common allergens present in house dust. Human patients clinically defined as allergic to horse could react with horse serum albumin by means of IgE or IgG antibodies. Studies regarding the specificities of these antibodies by inhibition enzyme-linked immunosorbent assay (ELISA) and depletion experiments have demonstrated that they are directed against dog serum albumin and cross-react not only with horse serum albumin but with other serum albumins from different origins. To investigate these observations further, we isolated and characterized three tryptic peptides (P1, P2 and P3) from horse serum albumin. The peptide P1 contains loops 1 and 2 of the first domain, P2 is derived from loop 4 of the second domain, and P3 contains the disulphide loop 9 of the third domain. These were able to inhibit the binding of the patients' IgE and IgG antibodies to horse albumin as well as to dog and cat serum albumins. This indicates that these peptides are involved in the observed cross-reactions. They also shared common epitopes, as revealed by human IgE antibodies. After reduction and alkylation, they totally lost their inhibitory capacity, suggesting that the intra-chain disulphide bridges, essential for the preservation of the loop structure, probably maintain their allergenic/antigenic reactivity.
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[18] - Cabanas R, Lopez-Serrano MC, Carreira J, Ventas P, Polo F, Caballero MT, et al. Importance of albumin in cross-reactivity among cat, dog and horse allergens. J Investig Allergol Clin Immunol 2000;10:71-77
Different allergenic proteins have been involved in cross-reactivity among animals. Albumins seem to be cross-sensitizing allergenic components. The aim of this study was to assess the importance of albumin as a cross-reactive allergen in patients sensitized to cat, dog and horse. One hundred and seventeen patients sensitized to cat were tested for IgE reactivity using skin prick tests and RAST assays with cat, dog and horse hair/dander extracts and their purified albumin extracts. RAST-inhibition studies were carried out to assess cross-reactivity among cat, dog and horse and among their purified albumins. It was found that 22% of patients exhibited specific IgE to cat albumin; 41% of patients sensitized to cat were also sensitized to dog and horse. Out of these patients, 21% had IgE to three albumins and 17% to two. Reciprocal inhibitions were observed among cat, dog and horse albumins and also among cat, dog and horse hair/dander extracts, using in the latter experiment sera from patients not sensitized to albumins. IgE binding to horse extract was inhibited 30% by its homologous albumin and IgE binding to cat and dog extracts in almost 15% by their respective albumins. It was concluded that albumins from these three animals share some epitopes that account for the cross-reactivity observed in around one-third of patients sensitized to cat, dog and horse. Nevertheless, more than 50% of specific IgE that cross-reacts among these three animals is directed to allergens other than albumin
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[19] - Spitzauer S, Pandjaitan B, Soregi G, Muhl S, Ebner C, Kraft D, et al. IgE cross-reactivities against albumins in patients allergic to animals. J Allergy Clin Immunol 1995;96:951-959
Type I allergic symptoms and severe asthma in particular are frequently caused by animal hair/dander proteins, among which albumins are possible cross-sensitizing allergenic components. METHODS: The significance and degree of IgE-cross-reactivities against various albumins were studied in a representative number (n = 200) of patients allergic to animals with hair/dander extracts, purified albumins from different animals, and a recombinant dog albumin fragment expressed in lysogenic Escherichia coli Y1089 and purified as a beta-galactosidase fusion protein. RESULTS: Despite a high degree of sequence homology among different albumins, a remarkable variability of IgE cross-reactivities was observed, indicating that some patients were sensitized preferentially against certain albumins. Most of the patients allergic to albumins, however, reacted to dog, cat, and horse albumin, which also bound a high percentage of albumin-specific IgE. CONCLUSION: The purified recombinant dog albumin fragment, representing 265 amino acids of the mature protein, bound IgE from all 15 patients allergic to albumin tested suggesting its potential usefulness for diagnosis and perhaps therapy.
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[20] - Spitzauer S, Swoboda I, Wiry I, Pandjaitan B, Brandejsky-Pichler F, Rumpold H, et al. Mapping of the IgE-reactive portions of cat and dog albumin by gene fragmentation. Int Arch Allergy Immunol 2001;124:95-96
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[21] - Spitzauer S, Pandjaitan B, Soregi G, Muhl S, Ebner C, Kraft D, et al. IgE cross-reactivities against albumins in patients allergic to animals. J Allergy Clin Immunol 1995;96:951-959
Type I allergic symptoms and severe asthma in particular are frequently caused by animal hair/dander proteins, among which albumins are possible cross-sensitizing allergenic components. METHODS: The significance and degree of IgE-cross-reactivities against various albumins were studied in a representative number (n = 200) of patients allergic to animals with hair/dander extracts, purified albumins from different animals, and a recombinant dog albumin fragment expressed in lysogenic Escherichia coli Y1089 and purified as a beta-galactosidase fusion protein. RESULTS: Despite a high degree of sequence homology among different albumins, a remarkable variability of IgE cross-reactivities was observed, indicating that some patients were sensitized preferentially against certain albumins. Most of the patients allergic to albumins, however, reacted to dog, cat, and horse albumin, which also bound a high percentage of albumin-specific IgE. CONCLUSION: The purified recombinant dog albumin fragment, representing 265 amino acids of the mature protein, bound IgE from all 15 patients allergic to albumin tested suggesting its potential usefulness for diagnosis and perhaps therapy.
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[22] - Spitzauer S, Schweiger C, Sperr WR, Pandjaitan B, Valent P, Muhl S, et al. Molecular characterization of dog albumin as a cross-reactive allergen. J Allergy Clin Immunol 1994;93:614-627
Indoor allergens comprise a group of allergenic proteins that are commonly derived from house dust mite and cat and dog dander. In addition to the two major dog allergens (molecular weights: 19 and 23 kd), dog albumin represents an important allergen for up to 35% of patients who are allergic to dogs. In IgE immunoblot inhibition studies and histamine release tests it has been demonstrated that patients who react to dog albumin exhibit IgE reactivity with purified albumins from cat, mouse, chicken, and rat. The proportion of dog-specific IgE directed against dog albumin was determined for patients allergic to dog albumin, and it ranges from 70% to 90%. By IgE immunoscreening of a lambda gt11 expression library from a dog salivary gland, we identified a number of reactive complementary DNA clones. All patients with IgE reactivity against natural dog albumin displayed IgE reactivity to the beta-galactosidase fusion protein encoded by clone 54c, which was therefore assumed to contain major IgE epitopes of dog albumin. The deduced amino acid sequence of clone 54c was compared with the Swiss-Prot library, and significant sequence homologies were found with albumins from different species (human: 82.6%, pig: 81.8%, cattle: 77.3%, sheep: 78.8%, mouse: 75.8%, and rat: 76.2%). Several other IgE-positive clones hybridized with oligonucleotides that were prepared according to this sequence. Partial complementary DNA coding for dog albumin fragments may be considered a useful tool for further characterization of major IgE epitopes of dog albumin.
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[23] - Hilger C, Swiontek K, Hentges F, de Blay F, Pauli G. Cross-sensitization to hemoglobin in a case of respiratory allergy to pork and food allergy to chicken meat. 3rd International Symposium on Molecular Allergology, Salzburg, April 18-20, 2008, Poster n°48
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