Respiratory allergy to Blomia tropicalis: Immune response in four syngeneic mouse strains and assessment of a low allergen-dose, short-term experimental model

Abstract

BackgroundThe dust mite Blomia tropicalis is an important source of aeroallergens in tropical areas. Although a mouse model for B. tropicalis extract (BtE)-induced asthma has been described, no study comparing different mouse strains in this asthma model has been reported. The relevance and reproducibility of experimental animal models of allergy depends on the genetic background of the animal, the molecular composition of the allergen and the experimental protocol.ObjectivesThis work had two objectives. The first was to study the anti-B. tropicalis allergic responses in different mouse strains using a short-term model of respiratory allergy to BtE. This study included the comparison of the allergic responses elicited by BtE with those elicited by ovalbumin in mice of the strain that responded better to BtE sensitization. The second objective was to investigate whether the best responder mouse strain could be used in an experimental model of allergy employing relatively low BtE doses.MethodsGroups of mice of four different syngeneic strains were sensitized subcutaneously with 100 μg of BtE on days 0 and 7 and challenged four times intranasally, at days 8, 10, 12, and 14, with 10 μg of BtE. A/J mice, that were the best responders to BtE sensitization, were used to compare the B. tropicalis-specific asthma experimental model with the conventional experimental model of ovalbumin (OVA)-specific asthma. A/J mice were also sensitized with a lower dose of BtE.ResultsMice of all strains had lung inflammatory-cell infiltration and increased levels of anti-BtE IgE antibodies, but these responses were significantly more intense in A/J mice than in CBA/J, BALB/c or C57BL/6J mice. Immunization of A/J mice with BtE induced a more intense airway eosinophil influx, higher levels of total IgE, similar airway hyperreactivity to methacholine but less intense mucous production, and lower levels of specific IgE, IgG1 and IgG2 antibodies than sensitization with OVA. Finally, immunization with a relatively low BtE dose (10 μg per subcutaneous injection per mouse) was able to sensitize A/J mice, which were the best responders to high-dose BtE immunization, for the development of allergy-associated immune and lung inflammatory responses.ConclusionsThe described short-term model of BtE-induced allergic lung disease is reproducible in different syngeneic mouse strains, and mice of the A/J strain was the most responsive to it. In addition, it was shown that OVA and BtE induce quantitatively different immune responses in A/J mice and that the experimental model can be set up with low amounts of BtE.

The Influence of Chitin on the Immune Response to the House Dust Mite Allergen Blo t 12

“…Interestingly, in agreement with other reports, this was also observed when mice were exposed to the whole B. tropicalis extract [58,59]. Although there were important differences in methacholine response, a similar level and pattern of inflammation was found among the groups receiving any of the two isoforms.…”

Ocimum gratissimum Linn. and rosmarinic acid, attenuate eosinophilic airway inflammation in an experimental model of respiratory allergy to Blomia tropicalis

“…The present study was conducted using a murine model of allergic airway disease induced by the sensitization to a common allergen, the B. tropicalis mite, which was previously characterized by our research group as leading to an increased number of eosinophils in the BAL fluid, to a marked influx of inflammatory cells into the lung around blood vessels and airways, and to airway luminal narrowing especially in A/J mice, the most sensitive to Bt amongst the tested strains [17]. This allowed us to investigate the potential antiallergic effect of an O. gratissimum extract, and the polyphenolic compound rosmarinic acid, in an experimental model of airway and lung inflammation induced by a clinically relevant aeroallergen.…”

“…The murine model of respiratory allergy was induced as we previously described [17]. Briefly, A/J mice (n = 5) were initially sensitized with two subcutaneous injections (day 0 and day 7) of Bt (10 μg of protein), adsorbed to 4 mg/mL of Al(OH) 3 in saline (Fig.…”

“…Additionally, tissue sections were stained with periodic acid Schiff to assess mucus presence. A quantitative digital morphometric analysis was performed as described previously [17].…”

GM-CSF–Licensed CD11b+ Lung Dendritic Cells Orchestrate Th2 Immunity to Blomia tropicalis

“…Sensitization to B. tropicalis allergens is thus an independent cause of allergy and asthma. In addition, although experimental mouse models of B. tropicalis extract-induced asthma using s.c. priming have been described (14), a more relevant model of allergic responses elicited by B. tropicalis solely via the respiratory route has yet to be reported, and little is known about regulation of Th2 responses in B. tropicalis extract-induced asthmatic models.…”