Characterisation of Dog Allergens by Means of Immunoblotting

Abstract

Sera from 75 patients with clinical type I allergy against dogs were investigated by means of immunoblotting using extracts prepared from dog hair/dander (CAN XI D) and saliva. In addition, selected sera were tested on extracts made of hair, skin, salivary glands (parotis and submandibularis), serum and liver. A 69-kD IgE-binding protein was identified in all extracts tested with an incidence of approximately 40% and shown to be dog albumin by means of inhibition experiments. In 96% of patients’ sera IgE antibodies reactive with a 19-kD and/or a 23-kD protein of the hair/dander extract (CAN XID) were observed. IgE binding to a 23-kD band was also detected in the hair and saliva extracts, but not in skin, salivary gland, serum and liver extracts. A 19-kD IgE-binding protein was strongly expressed in skin and to a lesser degree in saliva, but not in hair, serum and liver. Preincubation of patients sera with the hair extract and subsequent probing with the hair/dander extract (CAN XI D) inhibited IgE binding to the 23 kD protein whereas preincubation with the skin extract abolished IgE binding to the 19-kD protein. Using the hair/dander extract as inhibitor, IgE binding to the 19- and 23-kD proteins of saliva was abrogated. Thus it is concluded that the 23-kD protein is preferentially expressed in hair and saliva whereas the 19-kD protein is found in saliva and skin. Furthermore these two proteins are likely to represent immunologically independent major allergens.

Skin Prick Test Extracts for Dog Allergy Diagnosis Show Considerable Variations Regarding the Content of Major and Minor Dog Allergens

“…There may be several possible reasons for the observed heterogeneities of the extracts: (i) different starting material from which manufacturers extract allergens (hair, dander or/and epithelium) may contain different allergens [8,26], (ii) the levels of the major dog allergen Can f 1 may vary between dog breed and sex and between individual dogs of the same breed [27], (iii) different extraction techniques as well as the presence of stabilizers like glycerol and phenol might contribute to differences in extract composition [14,28]. …”

“…Can f 3, i.e. dog serum albumin, is an important cross-reactive allergen, and depending on the tested population up to 35% of dog-allergic patients reacted against Can f 3 [8,9]. Other dog allergens have been identified only recently, and they include a Fel-d-1-like allergen [10] and prostatic kallikrein [11].…”

Prostatic kallikrein: A new major dog allergen

“…1 Extracts of dog hair and dander contain a complexity of allergenic and nonallergenic proteins. 2,3 Three dog allergens have thus far been identified and studied in detail: Can f 1, Can f 2, and Can f 3. The former 2 are both members of the lipocalin protein family and have been purified and expressed as recombinant proteins.…”

Animal allergens and their control

“…These antigens are designated as Can f 1 and Can f 2 with molecular masses of 23 kd and 19 kd, respectively [11]. Like cat, major dog allergens can be found in hair, dander, and saliva, and are considered epithelial allergens [12].…”