Babakhin A.A.1, Laskin A.A.1, Kamishnikov O.Yu.1, Shershakova N.N.1, Shilovskiy I.P.1,
Berzhets V.M.2, Gushchin I.S.1, Khaitov M.R.1
1 Institute of Immunology, Moscow, Russian
2 Mechnikov’s Research Institute for Vaccines and Sera, Moscow, Russia
Key words: HDM Der p1 allergen extract, mouse model of asthma
Background. The purpose of this study was to develop a mouse model of asthma (MMA) using house dust mite Dermatophagoides
pteronyssinus (Der p) extract.
Methods. BALB/c mice were i.p. immunized with different doses of Der p lyophilized extract three times in three week
interval in the mixture with Al(OH)3. 8 weeks after the final immunization mice were challenged with Der p during
five consecutive days by intranasal applications (INA) or aerosol administration (AA). All mice were divided into 5
experimental groups: group 1 was immunized with 50 μg/mouse of Der p (in protein equivalent) in the mixture with
2 mg/mouse Al(OH)3 and challenged by INA; group 2 was immunized in the same way and challenged by AA; group 3
was immunized with 100 μg/mouse Der p in the mixture with 2 mg/mouse of Al(OH)3 and challenged by INA; group
4 was immunized in the same way and challenged by AA; group 5 (negative control) was immunized and challenged
with saline. 24 hours after the last challenge airway hyperresponsiveness (AHR) to different concentrations of methacholine
was evaluated in all groups by whole-body plethysmography. 48 hours after the last challenge in all groups
blood was collected for differential cell count, brochoalveolar lavage fluid (BALF) was sampled for the determination
of inflammatory cells and lungs were removed for histological analysis. Histopathological changes in lungs (allergic
inflammation) were graded according to semi-quantitative scoring system. Аnti-Der p IgE, IgG1 and IgG2a antibodies in
individual sera samples were detected by ELISA seven days after the last immunization and 48 hours after the challenge.
Results. The levels of anti-Der p IgE antibodies in groups 1–4 before as well as after the challenge were substantially
higher than that of in the group 5 (negative control). The highest level of serum Der p-specific IgE antibodies was
observed in the group 2. The levels of anti-Der p IgG1 and IgG2a antibodies in the groups 1–4 during all periods of
observation were higher than that of group 5 (negative control). At the same time the maximal levels of anti-Der p
IgG1 and IgG2a antibodies were observed in group 3 both after immunization and after challenge. The maximum of
AHR was observed in the groups 1 and 3 challenged by INA.
Analysis of cell composition in BALF demonstrated significant elevated number of eosinophils in group 3 in comparison
with group 5 (negative control) and other experimental groups. Regarding peripheral blood leukocyte count we observed
decreasing of band neutrophils in group 4 and increasing of segmented neutrophils in groups 1 and 3 in compare
to group 5 (negative control). In group 1 we found statistically significant decreasing of lymphocytes and increasing
of eosinophils in compare to negative control group 5. Histological picture of general allergic inflammation in lungs
as well as peribronchial and perivascular infiltration with inflammatory cells were the most noticeable (according to
score system) in group 3 in comparison with negative control group and other experimental groups.
Conclusion. Data obtained indicate that immunization (sensitization) of mice with Der p in a dose 100 μg/mouse together
with Al(OH)3 and challenge with Der p by mean of intranasal applications is a suitable approach for modeling
of mouse allergic asthma.