Microbial superantigens induce NF-kappa B in the human monocytic cell line THP-1.
Staphylococcal superantigens bind to MHC class II molecules and induce transcriptional activation of IL-1 beta and TNF-alpha genes in human monocytic cells. The understanding of the mechanisms by which superantigens activate cytokine gene expression is incomplete. In this study, we demonstrate that toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins A and B induce the activation of NF-kappa B, a transcriptional enhancer that binds to sequences found in both the IL-1 beta and TNF-alpha promoters. Electrophoretic mobility-shift assays showed a rapid induction of nuclear proteins that bound to the consensus kappa B motif. Furthermore, TSST-1 potently stimulated chloramphenicol acetyltransferase (CAT) expression by THP-1 cells transfected with a consensus NF-kappa B-promoter CAT construct, indicative of induction of NF-kappa B enhancer function. Induction of both NF-kappa B DNA-binding proteins and NF-kappa B enhancer function was down-regulated by inhibitors of protein kinase C and protein tyrosine kinase, indicating a role for these protein kinases in the induction of NF-kappa B by MHC class II ligands. Using neutralizing antibodies, we demonstrated that after the stimulation of cells with TSST-1, TNF-alpha, but not IL-1 beta, acted to up-regulate binding of NF-kappa B to DNA and the activation of the NF-kappa B-promoter CAT construct. These results indicate that induction of NF-kappa B by superantigens is up-regulated in part by an autocrine loop involving TNF-alpha.
Division of Immunology, Children's Hospital, Boston, MA 02115.
N S
NS
Trede
E
E
Castigli
R S
RS
Geha
T
T
Chatila
D000942:Antigens, Bacterial / Q000276:immunology*; D001427:Bacterial Toxins; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004768:Enterotoxins / Q000276:immunology*; D019833:Genistein; D006801:Humans; D007375:Interleukin-1 / Q000502:physiology; D007529:Isoflavones / Q000494:pharmacology; D007948:Leukemia, Monocytic, Acute / Q000378:metabolism; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000502:physiology; D013211:Staphylococcus aureus / Q000276:immunology; D018089:Superantigens; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
D000942:Antigens, Bacterial; D001427:Bacterial Toxins; D004268:DNA-Binding Proteins; D004768:Enterotoxins; D007375:Interleukin-1; D007529:Isoflavones; D016328:NF-kappa B; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C030107:enterotoxin F, Staphylococcal; D019833:Genistein; D011493:Protein Kinase C