<b>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</b>

The aim of this review is to show the impact of the use of purified and recombinant allergens to discriminate between co- and cross-sensitization to respiratory allergens. The author describes the evolution of diagnostic tests over the last decades; the tests initially allowed the detection of simultaneously positive cutaneous tests and/or simultaneous positivity of specific IgE to different allergen extracts, but they did not differentiate cross-sensitization from co-sensitization. RAST inhibition studies with crude extracts then established cross-reactivity, but did not identify the cross-reactive allergens involved. Later, immunoblot and CRIE inhibition were able to detect multiple cross-reactive allergens and to assess their physicochemical properties. But it is only since purified and recombinant allergens have been used in the different investigations that identification of cross-reactive allergens has been made possible at a molecular level. This historical approach is illustrated by examples selected from some of the main respiratory allergen sources: tree pollen, grass pollen, weed pollen, acarids, cockroaches and mammalians. For each of these allergen sources, the author gives an updated presentation of major and minor cross-reactive allergen molecules and refers to the last decade’s major publications concerning immunochemical investigations carried out in the field of cross-reactive respiratory allergens. Emphasis is placed on the clinical applications for allergic patients: improvement in the accuracy of the diagnosis of sensitization, new concepts of immunotherapy based on genetically engineered hypoallergenic variants of cross-reactive allergens used alone or in combination, evaluation of allergen load with environmental tests using monoclonal antibodies against cross-reactive allergens.

Section: Examples Selected Among the Main Respiratory Allergensmentioning

confidence: 57%

Section: Examples Selected Among the Main Respiratory Allergensmentioning

confidence: 99%

Evolution in the Understanding of Cross-Reactivities of Respiratory Allergens: The Role of Recombinant Allergens

Pauli

2000

“…However, allergens belonging to the same protein family and showing cross-reactivity are present in taxonomically distant animal species. One example is a 67-kDa albumin, which is present as allergen in nearly all of the above-mentioned species and which has been demonstrated as cross-reactive structure in cats, dogs, horses, mice, rats and guinea pigs [114,115,116]. Another example is the 21-kDa allergen lipocalin, which is cross-reactive between cat, horse and dog [117].…”

Section: Allergen Extracts Derived From Vertebratesmentioning

confidence: 99%

The Principle of Homologous Groups in Regulatory Affairs of Allergen Products – A Proposal

Lorenz

Lüttkopf

May

et al. 2008

Among other legal regulations, the Note for Guidance on Allergen Products CPMP/BWP/243/96 released by the European Medicines Agency provides regulatory instructions regarding the quality of allergen extracts for diagnostic or therapeutic purposes. The current revision of this guideline intends to transform the so-called ‘principle of taxonomic families’ to the ‘principle of homologous groups’. According to this concept, the data of one allergen extract demonstrating stability, efficacy and safety can, to a limited extent, be extrapolated to other allergen extracts belonging to the same homologous groups. The present work proposes the formation of homologous groups for pollen species and animal-derived materials on the basis of similar biochemical composition and homology/cross-reactivity of allergens or allergen sources. Some tree pollen species could be assigned to three different homologous groups, some weed pollen species to one homologous group and numerous grass pollen species to one homologous group on condition that data rely on single defined representative species. A homologous group for mites is limited to the Dermatophagoides species and the grouping of vertebrate-derived materials such as dander could be possible under restrictions. The criteria for the formation of the proposed homologous groups are illustrated in detail to provide an opportunity for extending existing homologous groups by further species in case of new insights in allergens and cross-reactivity of allergen sources. In this way, the concept of homologous groups could serve as a dynamic tool in the regulation of allergen products.

“…By RAST inhibition experiments, it was further demonstrated that certain monoclonal antibodies were able to inhibit binding of human IgE to cat and dog extracts [133]. Goubran Boutros et al used three short peptides, containing loops 1 and 2 of the first domain (peptide 1), loop 4 of the second domain (peptide 2), loop 9 of the third domain (peptide 3) to investigate the cross–antigenicity of horse serum albumin with albumins from dog and cat [134]. They were able to demonstrate that all three peptides contained epitopes shared by horse, cat and dog albumin [134].…”

Section: Ige–cross–reactivities With Animal Allergens: the Nature Of mentioning

confidence: 99%

“…Goubran Boutros et al used three short peptides, containing loops 1 and 2 of the first domain (peptide 1), loop 4 of the second domain (peptide 2), loop 9 of the third domain (peptide 3) to investigate the cross–antigenicity of horse serum albumin with albumins from dog and cat [134]. They were able to demonstrate that all three peptides contained epitopes shared by horse, cat and dog albumin [134]. The allergenic activity of rat serum albumin was studied using two proteolytic fragments of rat albumin in histamine release tests with basophils from patients allergic to rat albumin.…”

Section: Ige–cross–reactivities With Animal Allergens: the Nature Of mentioning

confidence: 99%

Allergy to Mammalian Proteins: At the Borderline between Foreign and Self?

Spitzauer

1999

Atopic individuals are characterized by their genetically determined tendency to mount IgE antibody responses against otherwise harmless antigens. Many of the environmental allergens (e. g., plant–, insect–, mould–derived allergens) are recognized as foreign intruders by the immune system. However, a substantial proportion of atopic individuals mount IgE responses to allergens of mammalian origin and, as recently reported, certain of them even react with human proteins (i. e., autoallergens). Through the application of molecular biological techniques for allergen characterization, the molecular nature and biological function of an increasing number of mammalian allergens have been revealed. This review provides a summary of well characterized mammalian allergens derived from hair/dander, saliva, serum and urine of animals (cat, dog, rodents, cow, horse) as well as of some recently characterized autoallergens. In addition, mammalian allergens were grouped in protein families with similar sequences and/or biological functions. The importance of cross–reactivities is exemplified for albumins which represent abundant mammalian serum proteins and highly cross–reactive allergens. Finally, possible advantages of using recombinant animal allergens for novel forms of component–resolved diagnosis and treatment of allergies to mammalian proteins are described.