Upregulation of nucleobindin expression in human‐activated lymphocytes and non‐Hodgkin's lymphoma

Nucleobindin (Nuc) was originally found to be an enhancement factor of antl-DNA antibody production secreted by a lymphold cell line derived from a lymphoprollferatlve MRL/Ipr mouse. It has been shown that Nuc has a unique structure containing a DNA- and two calcium-binding domains, and a leuclne zipper motif, but Its biological roles have not yet been fully elucidated. Expression of Nuc was first studied in human lymphocytes. Expression of Nuc mRNA in normal peripheral blood mononuclear cells was significantly increased upon mitogen stimulation. Anti-human Nuc monoclonal antibody H-1D8 immunopreclpitated Nuc protein in the nuclear extract of Molt-4 cells. Furthermore, in the immunohlstochemlcaf staining of tumor specimens from 108 patients with non-Hodgkin's lymphoma (NHL) with H-1D8, H-1D8-posltlve cells were observed in nearly all cases in varying frequency. According to the Working Formulation, the percentage of cases in which more than 90% of the tumor cells were stained with H-1D8 was 65% in the high grade of the histological malignancy, 54% In the Intermediate grade, and 22% in the low grade; however, normal ceils surrounding the tumor cells were virtually negative for H-1D8. These results showed that the level of Nuc expression in human lymphocytes reflects the status of activation or proliferation of the cells, thus providing a clue for the further investigation into biological roles of Nuc. In addition, It might be applicable to the clinlcopathological estimation of NHL as a novel Indicator.