Cat allergen induces proinflammatory responses by human monocyte-derived macrophages but not by dendritic cells

• BACKGROUND: The upper airway mucosa of healthy humans contains a dense network of cells with dendritic morphology of which the majority express a macrophage-like phenotype (CD14+CD64+CD68+), whereas the smaller population are immature dendritic cells (DC; CD11c+CD14-). Our aim was to study the proinflammatory response of human monocytes and in vitro-generated macrophages and DC after contact with cat allergens. METHODS: Monocyte-derived DC and monocyte-derived macrophages were exposed to cat allergen extract or Escherichia coli. Purified monocytes were stimulated with allergen extracts from cat or house dust mite (HDM) or the major allergenic protein Fel d 1 and induction of proinflammatory cytokines by monocytes was analyzed before and after blocking CD14. RESULTS: We show that cat allergen extract induced tumor necrosis factor (TNF) and interleukin (IL)-6 production by CD14-positive macrophages but not by CD14-negative DC. Moreover, monocytes produced significantly higher levels of TNF in response to cat allergens than in response to HDM allergens. We observed no differences in levels of TNF and IL-6 from either macrophages or monocytes after exposure to cat allergen when comparing healthy and cat-allergic individuals. Finally, the proinflammatory cytokine production from monocytes in response to cat allergen extract but not to HDM allergen was significantly reduced by blocking CD14. CONCLUSION: These results indicate that closely related innate immune cells from the myeloid lineage respond differentially to cat allergen extract and that the pattern-recognition receptor CD14 might be one of the mediators involved in the inflammatory responses to inhalant allergens.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Immunologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Immunology in the medical area (hsv//eng)

Keyword

Adult

Allergens/*immunology

Animals

Antigens

CD14/immunology

Antigens

Dermatophagoides/immunology

Cats

Dendritic Cells/*immunology

Escherichia coli/immunology

Glycoproteins/*immunology

Humans

Interleukin-6/biosynthesis

Macrophages/*immunology

Monocytes/immunology

Tumor Necrosis Factor-alpha/biosynthesis

Publication and Content Type

ref (subject category)

art (subject category)