Stress hormone epinephrine increases IgA transport across respiratory epithelial surfaces.
BACKGROUND
Secretory immunoglobulin A (sIgA) is the principle antibody produced at the respiratory surface. Respiratory sIgA levels are increased early after injury in both human and laboratory animals; the mechanisms are uncertain. Stress hormones, including epinephrine (Epi) and norepinephrine (NE), increase early after injury. In addition, respiratory epithelial cells are known to be responsive to β2-agonists. We therefore studied the effect of Epi, NE, and albuterol on IgA transport in vitro.


METHODS
Calu-3 respiratory epithelial cell monolayers grown in a 2-chamber cell culture system were treated for 24 hours with Epi, NE, or albuterol (10(-6)M). Dimeric IgA was added to the basal chamber of Calu-3 cells and IgA transcellular transport was indexed by recovery of SIgA in the apical chamber by enzyme-linked immunosorbent assay. In separate experiments, Klebsiella pneumoniae (10(5) colony-forming units/mL) was added to the apical chamber of treated Calu-3 cell monolayers and bacterial passage across Calu-3 cells was determined by bacterial recovery from basal chamber media. Calu-3 cells not treated with Epi, NE, or albuterol served as control. Cell monolayer integrity was confirmed by transepithelial electrical resistance.


RESULTS
Calu-3 cells treated with Epi led to a significant increase in sIgA transport, this was associated with an increase in polyimmunoglobulin receptor expression. Calu-3 cells treated with NE or albuterol showed no statistical difference compared with control. Only cells treated with Epi led to a significant increase in pro-inflammatory cytokine expression and decrease in bacterial passage.


CONCLUSIONS
Epinephrine is likely an early upstream signal in the enhanced IgA response at respiratory surfaces after injury.
Department of Surgery, Wayne State University, Detroit, MI. Electronic address: aaali@med.wayne.edu.
Abubaker
A
Ali
Department of Surgery, Wayne State University, Detroit, MI.
Lawrence
L
Diebel
Department of Surgery, Wayne State University, Detroit, MI.
David
D
Liberati
D000420:Albuterol / Q000494:pharmacology; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004837:Epinephrine / Q000494:pharmacology*; D004847:Epithelial Cells; D005434:Flow Cytometry; D006801:Humans; D007070:Immunoglobulin A / Q000378:metabolism*; D007711:Klebsiella pneumoniae; D009638:Norepinephrine / Q000494:pharmacology; D012137:Respiratory System / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
D016207:Cytokines; D007070:Immunoglobulin A; D000420:Albuterol; D009638:Norepinephrine; D004837:Epinephrine