Changes in CD11b and L-selectin expression on eosinophils are mediated by human lung fibroblasts in vitro

Am J Respir Crit Care Med. 1998 Sep;158(3):769-77. doi: 10.1164/ajrccm.158.3.9712143.

Abstract

Eosinophilic airway infiltration is a central feature in asthma. Eosinophils recovered from bronchoalveolar fluid show an activated phenotype, e.g., increased CD11b and decreased L-selectin expression. We investigated whether lung fibroblasts are able to activate eosinophils in vitro, and if so, which activating factor is most important. CD11b and L-selectin expression of isolated peripheral blood eosinophils were measured by flow cytometry after coculture with normal lung fibroblasts or their conditioned medium. We found that eosinophil CD11b expression increased (154% and 210%, p < 0.05) and L-selectin expression decreased (59% and 35.5%, p < 0.05) on eosinophils compared with baseline (100%) after 4 and 24 h of coculture with interleukin-1-beta (IL-1beta)-stimulated fibroblasts, respectively. Conditioned medium of stimulated fibroblasts also increased CD11b expression, but to a smaller extent (p < 0.05). L-selectin expression of eosinophils in cocultures was not different from that of eosinophils in conditioned medium. Only anti-granulocyte/macrophage colony-stimulating factor (anti-GM-CSF) reduced the activation of eosinophils in conditioned medium to almost basal levels (p < 0.05). An increase in CD11b expression is mediated by cytokines as well as direct cell contact, whereas a decrease in L-selectin expression is only mediated by cytokines. GM-CSF released by fibroblasts is an important factor in the modulation of both CD11b and L-selectin expression. These results show that lung fibroblasts can activate eosinophils by both adhesive interactions and by soluble factors.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Antibodies
  • Asthma / pathology
  • Bronchoalveolar Lavage Fluid / cytology
  • Cell Communication
  • Cell Survival
  • Cells, Cultured
  • Culture Media, Conditioned
  • Eosinophils / immunology*
  • Fibroblasts / immunology*
  • Flow Cytometry
  • Gene Expression Regulation
  • Granulocyte-Macrophage Colony-Stimulating Factor / analysis
  • Granulocyte-Macrophage Colony-Stimulating Factor / immunology
  • Humans
  • Interleukin-1 / immunology
  • L-Selectin / analysis*
  • L-Selectin / genetics
  • Lung / cytology*
  • Macrophage-1 Antigen / analysis*
  • Macrophage-1 Antigen / genetics
  • Phenotype
  • Time Factors

Substances

  • Antibodies
  • Culture Media, Conditioned
  • Interleukin-1
  • Macrophage-1 Antigen
  • L-Selectin
  • Granulocyte-Macrophage Colony-Stimulating Factor