title: Regulation of human monocyte HLA-DR and CD4 antigen expression, and antigen presentation by 1,25-dihydroxyvitamin D3.
abstract: 1,25-Dihydroxyvitamin D3 (1,25(OH)2-D) has been shown to be a macrophage-derived cytokine, capable of regulating myeloid differentiation and T-cell activation in vitro. Therefore, we examined the effects of 1,25(OH)2-D on the monocyte phenotype and function of human peripheral blood monocytes as an index of its biologic role at an inflammatory site. 1,25(OH)2-D treatment consistently and specifically reduced HLA-DR and CD4 expression by monocytes, while CD14 and class I HLA antigen expression were unaffected. Expression of Fc gamma R I-III on monocytes was variably modulated by 1,25(OH)2-D treatment, but no differences in antibody-dependent cell cytotoxicity (ADCC) were observed, measured using either ADCC or anti-Fc gamma R-antibody expressing hybridomas. In contrast, the ability of monocytes to induce antigen-dependent T-cell proliferation was markedly reduced by 1,25(OH)2-D pretreatment for as little as 6 hours. Addition of interleukin-1 (IL-1), IL-6, or indomethacin did not restore antigen-dependent T-cell proliferation, suggesting that this observation was not secondary to changes in IL-1, IL-6, or PGE2 production induced by 1,25(OH)2-D. These data suggest that 1,25(OH)2-D treatment specifically modulates human monocyte phenotype and function, altering HLA-DR antigen expression and antigen presentation, while leaving lytic function intact. These findings may be relevant to the immunobiologic role of 1,25(OH)2-D.
authors.affiliation: Department of Microbiology, Dartmouth-Hitchcock Medical Center, Hanover, NH.
authors.forename: W F
authors.initials: WF
authors.lastname: Rigby
authors.forename: M
authors.initials: M
authors.lastname: Waugh
authors.forename: R F
authors.initials: RF
authors.lastname: Graziano
mesh_terms: D000920:Antibody-Dependent Cell Cytotoxicity / Q000187:drug effects / Q000276:immunology / Q000502:physiology; D000938:Antigen-Presenting Cells / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D015704:CD4 Antigens / Q000235:genetics / Q000276:immunology*; D002117:Calcitriol / Q000378:metabolism / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects / Q000502:physiology; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects / Q000276:immunology* / Q000502:physiology; D010641:Phenotype
chemical_list: D015704:CD4 Antigens; D006684:HLA-DR Antigens; D002117:Calcitriol