Mite allergen induces nitric oxide production in alveolar macrophage cell lines via CD14/toll-like receptor 4, and is inhibited by surfactant protein D.
BACKGROUND
Previously, we have found that dust mite allergens can directly activate alveolar macrophages (AMs), induce inflammatory cytokines, and enhance T-helper type 2 cytokine production. A molecule of innate immunity in the lung, surfactant protein D (SP-D), is able to bind mite allergens and alleviates allergen-induced airway inflammation.


OBJECTIVE
This study was aimed at investigating the activation pathway of mite allergen (Dermatophagoides pteronyassinus, Der p)-induced nitric oxide (NO) production by AMs, and the role of SP-D in the modulation of activated AMs by mite allergens.


METHODS
Porcine SP-D was purified from bronchoalveolar lavage fluids of Lan-Yu mini-pigs, by affinity chromatography on maltose-sepharose. NO production, inducible expression of lipopolysaccharides (LPS)-related binding and responding surface receptors complex, CD14 and toll-like receptor 4 (TLR4), as well as inducible NO synthase (iNOs) and nuclear factor-kappaB activation were studied in two AMs cell lines, MH-S (BALB/c strain),and AMJ2-C11 (C57BL/6 strain), and one peritoneal macrophage cell line (RAW264.7), after stimulation with LPS, or Der p.


RESULTS
LPS and Der p elicited different responses of NO production in the different cell lines, and the response might depend upon the expression of the cell surface CD14/TLR4 complex in different genetic backgrounds of macrophage cell lines. Pretreatment of macrophages with SP-D could inhibit NO production from Der p or LPS-stimulated alveolar macrophages.


CONCLUSIONS
Mite allergen-induced alveolar macrophage activation is mediated by CD14/TLR4 receptors and can be inhibited by SP-D; it further supports the concept that SP-D may be an important modulator of allergen-induced pulmonary inflammation.
Liu
C-F
CF
Institutes of Basic Medicine, National Cheng-Kung University, Tainan, Taiwan.
Chen
Y-L
YL
Chang
W-T
WT
Shieh
C-C
CC
Yu
C-K
CK
Reid
K B M
KB
Wang
J-Y
JY
D000818:Animals; D039741:Antigens, Dermatophagoides / Q000494:pharmacology*; D060829:Arthropod Proteins; D015153:Blotting, Western / Q000379:methods; D002460:Cell Line; D003546:Cysteine Endopeptidases; D016207:Cytokines / Q000097:blood; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D005434:Flow Cytometry; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008070:Lipopolysaccharides; D008262:Macrophage Activation; D016676:Macrophages, Alveolar / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D009569:Nitric Oxide / Q000378:metabolism*; D009573:Nitrites / Q000032:analysis; D037663:Pulmonary Surfactant-Associated Protein D / Q000627:therapeutic use*; D013047:Specific Pathogen-Free Organisms; D015854:Up-Regulation
D039741:Antigens, Dermatophagoides; D060829:Arthropod Proteins; D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D009573:Nitrites; D037663:Pulmonary Surfactant-Associated Protein D; D009569:Nitric Oxide; D003546:Cysteine Endopeptidases; C451162:Dermatophagoides pteronyssinus antigen p 1