Cross-reactivity between group-5 and -21 mite allergens from Dermatophagoides farinae, Tyrophagus putrescentiae and Blomia tropicalis

Abstract

Abstract. Group-5 and group-21 allergens, produced by house dust mites and storage mites are 36.6-55.8% identical in their sequences and are recognized by at least 50% of immunoglobulin (Ig)E from the sera of individuals allergic to dust mites. In the present study, recombinant group-5 and -21 allergens from three mite species, Dermatophagoides farinae (rDer f 5 and 21), Tyrophagus putrescentiae (rTyr p 5 and 21), and Blomia tropicalis (rBlo t 5 and 21), were purified from Escherichia coli, and the IgE reactivities and cross-reactivities of these allergen variants were assessed. The IgE binding frequencies of rDer f 5, rDer f 21, rTyr p 5, rTyr p 21, rBlo t and rBlo t 21 proteins were 64. 95, 65.98, 30.41, 41.24, 30.93 and 21.65%, respectively. The IgE reactivity of rDer f 5 correlated highly with that of rDer f 21 (r=0.733). rTyr p 5 exhibited the highest level of correlation with rTyr p 21 (r=0.950), while the correlation of rBlo t 5 with rBlo t 21 was the lowest observed (r=0.104). The binding of IgE to rDer f 5 and rDer f 21 was not inhibited by any allergens but themselves. While rDer f 5 inhibited only 60.3% of IgE binding to rBlo t 5, rDer f 21 exhibited a high inhibitory effect against rTyr p 5 (93.01%), rTyr p 21 (92.12%), rBlo t 5 (86.97%) and rBlo t 21 (70.30%), implying cross-reactivity among mite species. The results of the present study demonstrated that the majority of the IgE reactivity to group-5 and -21 storage mite allergens is due to cross-reaction. It is therefore imperative to develop an accurate, component-resolved diagnosis for dust mite allergies.

Allergens of <b><i>Blomia tropicalis</i></b>: An Overview of Recombinant Molecules

“…In contrast, most studies have focused on cross-reactivity between B. tropicalis and other mites [33,53,101,107]. At least 5 cross-reactive allergens have been identified in extracts of Euroglyphus maynei and B. tropicalis [108].…”

“…Despite the low sequence identity scores, some degree of cross-reactivity between group 5 and 21 allergens of B. tropicalis and Dermatophagoides has been reported; however, while Der f 5 could inhibit 60% of IgE binding to Blo t 5, there was no inhibition in the opposite direction [53]. Similarly, the cross-reactivity between Der p 1 and Blo t 1 was shown to be moderate [32], as was that between Blo t 5 and Der p 5 [43].…”

“…Figure 1e shows the identified B cell epitopes on the Blo t 5 structure. Recent studies have also evaluated the cross-reactivity between rBlo t 5 and the group 21 allergens, as well as with crude extracts of B. tropicalis and Ascaris lumbricoides [12,53]. The latter allergen source should be considered in tropical regions due to the high prevalence of helminth infections [54,55,56], which could possibly interfere with the serodiagnosis of mite allergy [57,58].…”

Relación filogenética de ácaros Glyciphagidae, Pyroglyphidae, Chortoglyphidae y Acaridae, según la secuencia de sus alérgenos

“…7,8 En los países del trópico, los ácaros son la principal causa de atopia; 9,10 los mayormente reportados son Dermatophagoides pteronyssinus, Dermatophagoides farinae y Blomia tropicalis. 11,12,13,14 Los estudios epidemiológicos han mostrado que no todas las poblaciones están expuestas a los diferentes ácaros en la misma proporción, 6,7 sin embargo, debido a la reactividad cruzada entre algunas proteínas, las personas que tienen una sensibilización IgE a proteínas que se mantienen conservadas entre diferentes especies, pueden presentar síntomas con fuentes a las que no están expuestos si estas presentan estas proteínas. 15 Usualmente esto ocurre entre proteínas fi logenéticamente conservadas con alta identidad que reciben el nombre de "panalérgenos" y están presentes en fuentes ancestralmente relacionadas.…”

Clinical Response to Subcutaneous <b><i>Dermatophagoides pteronyssinus</i></b> Immunotherapy in Children with Allergic Rhinitis and Asthma Is Independent of Sensitization to <b><i>Blomia tropicalis</i></b> Allergens

“…Studies have shown that more than 80% of BT sensitized patients react to Blo t 5 and Blo t 21 [23]. Blo t 5 and Blo t 21 share a moderate degree of homology, but the IgE cross-reactivity between the 2 allergens is very limited [24-26]. Thus, Blo t 5 or Blo t 21 are defined as BTMA [27, 28].…”