Summary
Humulus pollen is an important cause of allergic asthma in East
Asia. There have been some murine models for Humulus pollen
allergy established by intraperitoneal (IP) sensitization and nasal drip
stimulation, but they were not comprehensive enough. Here, we used
atomized inhalation for challenge and compared the subcutaneous (SC) and
IP sensitization routes to determine the optimal method to establish a
model of asthma induced by Humulus pollen. Subsequently, we tried
to develop a rapid subcutaneous immunotherapy (SCIT) model.
Mice were sensitized through the
SC or IP route and challenged with Humulus pollen extract to
induce asthma. To compare the two sensitization methods, airway
hyperresponsiveness (AHR), inflammatory cell infiltration,
allergen-specific serum
immunoglobulin (Ig)E (sIgE) levels, cytokine levels, and lung
histopathology were assessed. The effects of SCIT (once every other day
for 16 days) on airway inflammation, AHR, sIgE, and
allergen-specific serum IgG2a
(sIgG2a) levels were evaluated by using the model established. Although
mice sensitized by the SC or IP routes both showed AHR and airway
inflammation, the SC route elicited significantly higher levels of sIgE,
eosinophil inflammation, and T helper type 2 cytokines, compared with
the IP route. SCIT in the treatment group significantly reduced the
titers of sIgE, enhanced the titers of sIgG2a, and effectively
alleviated pulmonary inflammation and AHR, compared with the vehicle
group. These observations indicate that the
SC
route can be a better sensitization route than IP route for establishing
a murine model of Humulus pollen allergy; short-term SCIT
improved symptoms and pathophysiology in asthmatic mice.
Keywords: Humulus pollen; murine model of asthma;
subcutaneous immunotherapy; SC route; IP route