CD14 IS EXPRESSED AND FUNCTIONAL IN HUMAN B-CELLS

The human B cell line RPMI 8226 exhibits variable staining with the CD14 antibody My4. We have isolated three stable clones from this line with clones 1 and 2 being My4 positive and clone 3 My4 negative. Similar to previous results in monocytes, immunoprecipitation with the My4 antibody revealed a 54-kDa cell surface molecule, analysis of supernatants showed soluble CD14, and Northern blotting demonstrated a 1.4-kb transcript in clones 1 and 2, but not in clone 3, which suggests that the My4 antibody detects CD14 in clones 1 and 2. This CD14 molecule was functional in that lipopolysaccharide stimulation induced interleukin (IL)-6 and IL-10 in clones 1 and 2 but not in clone 3. Furthermore, the My4 antibody was capable of blocking these responses at the transcript and protein levels. Finally, peripheral blood B cells were highly purified by cell sorting (> 98% CD19 positive). These cells produced IL-6 in response to lipopolysaccharide, and this response was blocked by anti-CD14 antiserum. Thus, our findings demonstrated that human B cells can express functionally active CD14.