The expression of the DBF (vitamin D binding protein) gene was investigated in monocytes and in peripheral blood lymphocytes. DBF message was amplified through 35 cycles of PCR amplification using specific oligonucleotide primers. PCR products of the expected size were further identified by Southern blotting using a specific DBF probe. No expression of the DBF gene could be detected in peripheral blood lymphocytes, nor in the monocyte-derived U 937 cell line. In contrast, message for DBF was identified in monocytes activated with lipopolysaccharide when analyzed between 6 and 10 h following stimulation. These results suggest that the temporal expression of the DBF gene could play a major role in the activation of monocytes by 1-25(OH)2D3.
