The expression of membrane-bound CD14 renders mouse B-1 cells susceptible to LPS

The surface expression of CD14 on mouse B-1 cells and its role on their response to lipopolysaccharide (LPS) were studied by using the murine TH2.52 B-1 cell line and peritoneal B-1 cells. TH2.52 cells with the B-1 phenotype were found to express membrane-bound CD14. Furthermore, CD14 was expressed on physiological peritoneal CD5⁺ B-1 cells. The stimulation of CD14-expressing TH2.52 cells with a low concentration of LPS resulted in the activation of nuclear factor (NF)-κB and a mitogen-activated protein kinase (MAPK). The LPS-induced NF-κB and MAPK activation was markedly inhibited by anti-CD14 antibody. These results suggest that B-1 cells may respond to LPS via membrane-bound CD14.