Lipopolysaccharide uptake is augmented in lipopolysaccharide‐tolerant mouse macrophage‐like cells via increased CD14 expression

Lipopolysaccharide (LPS) tolerance can be recognized as a modulation of innate immune responses rather than merely a hyporesponsiveness to LPS, with CD14 being crucial for both LPS uptake and LPS signaling. In this study, we observed that LPS-tolerant mouse macrophage-like cells, in which LPS-induced TNF-α and IFN-β production was suppressed, exhibited a dramatic increase in surface CD14 expression. Also, we found that LPS uptake was enhanced in LPS-tolerant mouse macrophage-like cells, but not when treated with an anti-CD14 antibody. While previous studies have reported increased CD14 expression and enhanced LPS uptake in LPS-tolerant cells, our findings reveal that overexpressed CD14 in LPS-tolerant mouse macrophage-like cells is responsible for the enhanced LPS uptake in these cells.