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Updated: Aug 12, 2026

In Vitro Assay to Evaluate the Impact of Immunoregulatory Pathways on HIV-specific CD4 T Cell Effector Function
Published on: October 16, 2013
Modulation of the expression of CD4 on HL-60 cells by exposure to 1,25-dihydroxyvitamin D3
M Schlesinger1, Z Bar-Shavit, R Hadar
1Hubert H. Humphrey Center for Experimental Medicine and Cancer Research, Hebrew University, Hadassah Medical School, Jerusalem, Israel.
Abstract:
The CD4 molecule functions as a receptor for the binding and infectivity of the human immunodeficiency virus (HIV). It is of interest, therefore, to develop procedures for its down-regulation. In the present study, the effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) on the expression of cell surface antigens of the HL-60 promyelocytic leukemia cell line was analyzed. Exposure of HL-60 cells to 1,25(OH)2D3 resulted in down-regulation of CD4 as assessed by their staining with the Leu-3a monoclonal antibody (MoAb). This treatment increased the staining of HL-60 cells with the monocyte-specific 63D3 MoAb. In contrast to the rapid elimination of cell surface CD4 by exposure of HL-60 to phorbol myristate acetate (PMA), the maximal reduction of CD4 by 1,25(OH)2D3 was attained within 48 h after the beginning of the exposure.

