LPS induced translocation of NF-κB occurs only in a subpopulation of CD14-positive mononuclear cells

Abstract

CD14-receptor occupancy is a potent activator of the ubiquitous transcription factor NF-κB. In resting cells, NF-κB exists as a heterodimer in the cytoplasm bound to its inhibitor IκB. Upon stimulation with lipopolysaccharide (LPS), NF-κB translocates to the nucleus. By means of immunohistochemistry, nuclear translocation of the p65 subunit was detected in LPS-stimulated mononuclear cells at the single-cell level. Double-staining experiments showed nuclear translocation of p65 in only a fraction (< 50%) of the LPS-stimulated CD14-positive cells. In vivo, similar results were obtained. In blood from healthy volunteers who were infused with LPS, only a fraction of the CD14-positive cells showed translocation of the p65 subunit. In conclusion, we identified the translocation of NF-κB after LPS stimulation at the single cell level in vitro and in vivo. Surprisingly, only a subpopulation of CD14-positive cells showed translocation. These data indicate that the mere expression of CD14 alone is insufficient for LPS-responsiveness.