Interleukin-8 (IL-8) is a major neutrophil chemotaxin from human alveolar macrophages stimulated with staphylococcal enterotoxin A (SEA).
Since Staphylococcus aureus is an important human pathogen, and infection of the lungs is characterized by neutrophil infiltration we studied the role of a staphylococcal toxin, enterotoxin A (SEA) on the synthesis and secretion of IL-8 by human alveolar macrophages. As SEA concentration was increased, the IL-8 accumulation in the macrophage conditioned medium increased. The concentration of mRNA encoding IL-8 was also elevated in the macrophage in response to increases in SEA concentration. Although the monocytic cell line U937 was able to respond to SEA and secrete IL-8, treatment with PMA prior to SEA stimulation increased the IL-8 accumulation around fifty fold indicating that maturation of the undifferentiated cell to a more macrophage-like cell facilitated IL-8 accumulation. Stimulating human alveolar macrophages with high concentrations of SEA caused an increase in IL-1 accumulation. However, when the cells were incubated with SEA in the presence of IL-1 receptor antagonist, there was no decrease in IL-8 accumulation. Addition of a neutralizing anti-IL-8 monoclonal antibody to the culture medium of SEA-stimulated macrophages significantly reduced the neutrophil chemotactic activity of the medium. These studies showed that IL-8 is a major neutrophil chemotaxin from human alveolar macrophages stimulated with SEA.
Miller
E J
EJ
Department of Biochemistry, University of Texas Health Center, Tyler 75710-2003, USA.
Nagao
S
S
Carr
F K
FK
Noble
J M
JM
Cohen
A B
AB
D015152:Blotting, Northern; D002630:Chemotactic Factors / Q000502:physiology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004768:Enterotoxins / Q000494:pharmacology*; D006801:Humans; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism / Q000502:physiology*; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000302:isolation & purification; D013268:Stimulation, Chemical; D018089:Superantigens / Q000494:pharmacology*
D002630:Chemotactic Factors; D004768:Enterotoxins; D007375:Interleukin-1; D016209:Interleukin-8; D012333:RNA, Messenger; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal