A high-molecular-weight mite antigen (HM1) fraction aggravates airway hyperresponsiveness of allergic mice to house dusts and whole mite cultures.
BACKGROUND
The house dust mite Dermatophagoides farinae is the most common aeroallergen causing human allergic asthma. Previously, we demonstrated that a high-molecular-weight allergenic fraction (HM1), which was abundant in D. farinae extracts, induced a proliferative response of T cells from healthy donors. The induction was mediated through the activation of macrophages without MHC class II restriction. In this study, we investigate whether HM1 influences the development of airway inflammation in murine models of asthma.


METHODS
BALB/c mice were injected twice intraperitoneally with D. farinae fecal extract (Dff) at an interval of 5 days. They were exposed daily to aerosolized antigen (group 1: Dff, group 2: HM1, group 3: HM1-depleted Dff and group 4: PBS) for 10 days. The effect of HM1 on their airway inflammation was evaluated by measuring acetylcholine-induced airway hyperresponsiveness and inflammatory cell infiltration in lung tissue.


RESULTS
The inhalation of the whole fecal extract or the HM1 fraction induced airway hyperresponsiveness which was detectable after 24 h and was maintained for as long as 120 h. The inhalation of extract depleted of the HM1 fraction induced hyperresponsiveness measured at 24 h but this was not maintained for 120 h. Macrophage infiltration was significantly prolonged in mice inhaling the whole extract and the HM1 fraction compared to the HM1-depleted extract.


CONCLUSIONS
The inhalation of the high-molecular-weight HM1 fraction of D. farinae prolonged airway hyperresponsiveness and macrophage inflammation in a mouse model of hypersensitivity. The results indicate that the HM1 fraction which can induce T cell proliferation through macrophage activation may play a role in the duration of airway responsiveness.
Tategaki
Airo
A
Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashi-Hiroshima, Japan. lovero@hiroshima-u.ac.jp
Kawamoto
Seiji
S
Okuda
Takahide
T
Aki
Tsunehiro
T
Yasueda
Hiroshi
H
Suzuki
Osamu
O
Ono
Kazuhisa
K
Shigeta
Seiko
S
D016902:Air Pollution, Indoor / Q000009:adverse effects; D000485:Allergens / Q000009:adverse effects* / Q000276:immunology* / Q000494:pharmacology; D000818:Animals; D039741:Antigens, Dermatophagoides / Q000009:adverse effects / Q000276:immunology / Q000494:pharmacology; D060829:Arthropod Proteins; D001985:Bronchial Provocation Tests; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology; D039481:CD11b Antigen / Q000187:drug effects / Q000276:immunology; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D003546:Cysteine Endopeptidases; D004195:Disease Models, Animal; D004306:Dose-Response Relationship, Immunologic; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008970:Molecular Weight; D039981:Pyroglyphidae / Q000276:immunology*; D012130:Respiratory Hypersensitivity / Q000209:etiology*; D013223:Statistics as Topic; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology
D000485:Allergens; D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D039481:CD11b Antigen; D003546:Cysteine Endopeptidases; C451159:Dermatophagoides farinae antigen f 1