Effect of SC or IP route sensitization on airway inflammation
and immunological response
Compared with the respective control groups, mice sensitized with HSE by
either the IP or SC routes both developed severe AHR to Mch,
characterized by significantly greater Penh values at 6.25, 12.5, 25 and
50 mg/mL of Mch inhalation (Fig. 2A, P<0.01 or
P<0.05). These changes were accompanied by recruitment of
total white blood cells and inflammatory cell subpopulations (e.g.,
eosinophils and neutrophils) to the airways (Fig. 2C1,P<0.01,
respectively); elevated levels of IL-13 (Fig. 2D2, P<0.01) and
IL-10 (Fig. 2D4,
P<0.05)
in the BALF; inflammatory infiltrates around bronchi; and elevated mucus
production (Fig. 3C, P<0.01).In contrast, IL-13 (Fig. 2D2)
levels and IL-10 (Fig. 2D4) levels in SHS, and IFN-γ (Fig. 2D3) levels
in both BALF and SHS, did not show any clear changes in HSE-sensitized
mice, compared with the respective control groups.
In addition, compared with mice in the SC.PBS group, mice sensitized
with HSE by the SC route developed higher HSE-specific serum IgE levels
(Fig. 2B, P<0.01);
higher numbers (Fig.
2C1,P<0.01) and percentages
(Fig. 2C2, P<0.01) of
BALF eosinophils; and higher production of IL-4 in BALF (Fig. 2D1,
P<0.01) and SHS (Fig.
2D1, P<0.05). However, these characteristics were not observed
in the IP.HSE group, compared with the IP.PBS group
(Fig. 2B, C1, C2, and D1).
Notably, HSE-specific serum IgE
levels (Fig. 2B,
P<0.01); numbers (Fig.
2C1, P<0.01) and
percentages (Fig. 2C2,
P<0.01) of BALF eosinophils; and production of IL-4 in BALF
(Fig. 2D1, P<0.05) and
SHS (Fig. 2D1, P<0.05)
were all significantly higher in the SC.HSE group than in the IP.HSE
group.
Futhermore, the protein profile of HSE (determined by SDS-PAGE) is shown
in Fig. 4A; the molecular weight of the proteins mainly ranged from 10
kDa to 100 kDa. Most sera from animals in the SC.HSE and IP.HSE groups
exhibited IgE reactivity against HSE proteins with apparent molecular
masses of 48–100 kDa (Fig. 4B). There were no significant differences
in the distribution of immunoreactive bands between animals in the
SC.HSE and IP.HSE groups. Pooled sera of animals in the control group
showed no binding of IgE to HSE.