Endotoxin tolerance from lipopolysaccharide pretreatment induces nuclear factor-kappa B alterations not present in C3H/HeJ mice

Background: Lipopolysaccharide (LPS) activation of macrophage (MO) cytokine secretion requires activation and translocation of nuclear factor-kappa B (NF-kappa B), Endotoxin tolerance induced in LPS-responsive C3H/HeN MO by L PS pretreatment results in decreased tumor necrosis factor (TNF) secretion and altered NF-kappa B activation. C3H/HeJ M empty set s have a genetic def ect that renders them tolerant to LPS activation, We hypothesized that the alterations of NF-kappa B activation seen with LPS tolerance in HeN MO woul d be present in HeJ mice. Methods: MO from C3H/HeJ and C3H/HeN mice were cultured with +/- 10 ng/mL L PS pretreatment for 24 hours and then stimulated with 1 to 1,000 ng/mL LPS. Activation of NF-kappa B was assayed by gel shift using a P-32-labeled spe cific oligonucleotide 30 minutes after LPS activation. TNF secretion 6 hour s after LPS stimulation was measured by bioassay. Results: LPS stimulation activated NF-kappa B in both HeN and HeJ MO. We ob served decreased NF-kappa B activation and a characteristic mobility shift in endotoxin-tolerant MO from HeN mice that were not present in HeJ MO. In contrast with the results in HeN mice, LPS pretreatment did not induce any alterations in NF-kappa B activation in HeJ MO. LPS-stimulated TNF secretio n was decreased in HeN MO after LPS pretreatment, There was no change in TN F secretion in HeJ MO, but, overall, TNF secretion by these cells was much less than that seen in HeN cells. Conclusion: MO from C3H/HeN mice rendered LPS-tolerant by low-dose LPS pret reatment have alterations in activation of MF-kappa B not present in LPS-hy poresponsive C3H/HeJ mice.