Quantitative comparison of C-X-C chemokines produced by endotoxin-stimulated human alveolar macrophages.
The C-X-C chemokines are a structurally related and functionally redundant family of proteins with neutrophil chemotactic activity. Many of the C-X-C chemokines are produced by endotoxin-stimulated alveolar macrophages (AMs), but knowledge of their relative quantities and their relative contributions to the total chemotactic activity released from these cells is incomplete. Human AMs were stimulated with or without Escherichia coli endotoxin for 2, 4, 8, and 24 h. The mRNA sequences of interleukin (IL)-8, the 78-amino acid epithelial cell-derived neutrophil activator (ENA-78), growth-related protein (GRO) alpha, GRObeta, and GROgamma were cloned by PCR and identified by sequence analysis. The relative mRNA quantities were compared by Northern analysis, and IL-8 was found to predominate. Similarly, IL-8 protein concentrations in the cell supernatants were consistently higher than either the ENA-78 or GRO concentration, and by 24 h, IL-8 concentrations were 10-fold higher than those of the other C-X-C chemokines. Blocking polyclonal antibodies to IL-8 substantially reduced the chemotactic activity in the AM supernatants, whereas antibodies to ENA-78 and GRO had little or no effect. We conclude that IL-8 is the predominant C-X-C chemokine and the dominant neutrophil chemoattractant accumulating in 24-h supernatants of lipopolysaccharide-stimulated human AMs. These studies provide insight into potentially effective strategies of interrupting AM-derived inflammatory signals in the lungs.
Goodman
R B
RB
Medical Research Service, Seattle Veterans Affairs Medical Center, Seattle, Washington 98108, USA.
Strieter
R M
RM
Frevert
C W
CW
Cummings
C J
CJ
Tekamp-Olson
P
P
Kunkel
S L
SL
Walz
A
A
Martin
T R
TR
D000595:Amino Acid Sequence; D000704:Analysis of Variance; D001483:Base Sequence; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D054365:Chemokine CXCL5; D019743:Chemokines, CXC / Q000096:biosynthesis*; D002630:Chemotactic Factors / Q000096:biosynthesis; D003001:Cloning, Molecular; D004731:Endotoxins / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli; D006133:Growth Substances / Q000096:biosynthesis; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8 / Q000031:analogs & derivatives / Q000096:biosynthesis; D007700:Kinetics; D016676:Macrophages, Alveolar / Q000187:drug effects / Q000502:physiology*; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000096:biosynthesis; D016415:Sequence Alignment; D012689:Sequence Homology, Nucleic Acid; D013997:Time Factors; D014158:Transcription, Genetic; D001620:beta-Thromboglobulin
C475829:CXCL1 protein, human; C499706:CXCL2 protein, human; C486263:CXCL5 protein, human; D054360:Chemokine CXCL1; D054426:Chemokine CXCL2; D054365:Chemokine CXCL5; D019743:Chemokines, CXC; D002630:Chemotactic Factors; D004731:Endotoxins; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; C061615:PPBP protein, human; D010455:Peptides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D001620:beta-Thromboglobulin; C009862:connective tissue-activating peptide