Introduction:

The House Dust Mite Blomia tropicalis (Bt) is an important etiological agent of allergic asthma in tropical areas. Bt is substantially apart from the genus Dermatophagoides, which is more common globally. The objective of this paper was to assess the immunobiological features of Bt allergens.

Methods:

Purified allergens from Bt cultures were used, based on a technological platform developed at BIOCEN. Bt formulations were evaluated in murine models of respiratory allergy and in clinical studies of asthma immunotherapy with the VALERGEN®-BT vaccine. Mass spectrometry was used for molecular characterization and anti-Blo_t_13 monoclonal antibodies, obtained in BIOCEN, for epitope mapping.

Results and Discussion:

For the first time, the interaction of Bt allergens with innate immunity TLR receptors and the induction of neutrophilic inflammation, a known feature of the severe asthma phenotype, was identified. Native Blo_t_2 was identified as the predominant component of allergenic extracts, showing high IgE binding frequency in Cuban asthmatics (80 %), greater than Blo_t_5, currently considered the major allergen. Moreover, the IgE epitopes and cross-reactivity to human proteins of another Bt allergen, Blo_t_13, were identified. The first piece of evidence in humans of the specific and non-cross-reactive effect of Bt immunotherapy towards Dermatophagoides allergens was obtained. These results guided the design of a second-generation therapeutic vaccine, Prolinem®-BT, using alumina and TLR4 ligands as adjuvants. Its preclinical development results showed its antiallergic effect with only three doses, and its safety. Conclusion: Overall, these results confirm the need for the inclusion of Bt-specific immunotherapy for the effective management of allergic asthma in tropical countries.

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