CD14(+) cells are necessary for increased survival of eosinophils in response to lipopolysaccharide.
There has been considerable interest in the effect that gram-negative bacterial endotoxin (lipopolysaccharide [LPS]) can have in asthma, given that inhalation of LPS has been shown to cause bronchial hyperresponsiveness. Further, there is evidence that the endotoxin-binding protein CD14 may be a marker for asthma. Inhaled LPS has been shown to cause an influx of eosinophils into the nasal airway and to increase the survival of CD16-negatively selected eosinophils in vitro. In this study, we compared survival of eosinophils isolated via CD16-negative selection with eosinophils that were isolated using both CD16- and CD14-negative selection criteria. Survival of CD16-negatively selected eosinophils was enhanced by LPS in a dose-dependent manner and was inhibited by the endotoxin antagonists polymyxin B or lipid X. In contrast, depletion of CD14(+) cells within the eosinophil preparations (CD14/CD16-negatively selected eosinophils) decreased the effect of LPS on survival. Preincubation of CD16-negatively selected eosinophils with antibody 60bd, which blocks LPS binding to CD14, prevented the survival-enhancing effect of LPS. However, CD14 was not detected on eosinophils by flow cytometry, even after incubation with LPS for up to 24 h. These results suggest that the survival-enhancing effect of LPS on eosinophils requires the presence of CD14(+) cells in the population. It is our hypothesis that enhanced eosinophil survival with LPS involves the contribution of another cell type.
Meerschaert
J
J
Departments of Medicine and Biomolecular Chemistry, University of Wisconsin, Madison, Wisconsin, USA. Jmeerschaert@stcloudstate.edu
Busse
W W
WW
Bertics
P J
PJ
Mosher
D F
DF
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D016207:Cytokines / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004804:Eosinophils / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D005312:Fetal Blood; D005434:Flow Cytometry; D006801:Humans; D006825:Hybridomas; D018950:Lipopolysaccharide Receptors / Q000032:analysis* / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017452:Receptors, IgG / Q000032:analysis
D000911:Antibodies, Monoclonal; D003470:Culture Media; D016895:Culture Media, Serum-Free; D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D017452:Receptors, IgG