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Full-Text Articles in Medicine and Health Sciences
Inhibition Of T Lymphocyte Mitogenesis By 1,25-Dihydroxyvitamin D3 (Calcitriol)., William F.C. Rigby, Terryl Stacy, Michael W. Fanger
Inhibition Of T Lymphocyte Mitogenesis By 1,25-Dihydroxyvitamin D3 (Calcitriol)., William F.C. Rigby, Terryl Stacy, Michael W. Fanger
Dartmouth Scholarship
Recent studies have suggested that vitamin D may have other important biologic activities in addition to its well-characterized role in the maintenance of calcium homeostasis. Discovery of cytosolic receptors for vitamin D in human peripheral blood monocytes and lectin-stimulated lymphocytes prompted us to study the effects of 1,25-dihydroxyvitamin D3 (calcitriol), the most biologically active metabolite of vitamin D, upon phytohemagglutinin (PHA)-induced lymphocyte blast transformation. We have found that calcitriol is a potent inhibitor of PHA-induced lymphocyte proliferation, achieving 70% inhibition of tritiated thymidine incorporation after 72 h in culture. Furthermore, calcitriol suppressed interleukin-2 (IL-2) production by PHA-stimulated peripheral blood mononuclear …
Inhibition Of Growth Of Toxoplasma Gondii In Cultured Fibroblasts By Human Recombinant Gamma Interferon., E. R. Pfefferkorn, Paul M. Guyre
Inhibition Of Growth Of Toxoplasma Gondii In Cultured Fibroblasts By Human Recombinant Gamma Interferon., E. R. Pfefferkorn, Paul M. Guyre
Dartmouth Scholarship
The growth of Toxoplasma gondii in cultured human fibroblasts was inhibited by recombinant human gamma interferon at concentrations of 8 to 16 U/ml. The interferon was titrated by observing a total inhibition of parasite plaque formation 7 days after infection. Inhibition of the growth of T. gondii in the early days after infection was measured by marked reductions in the incorporation of radioactive uracil, a precursor that can only be used by the parasites. This assay showed that when cells were pretreated with gamma interferon for 1 day and then infected, inhibition of T. gondii growth could be readily detected …
Gamma Interferon Induces Monocytoid Differentiation In The Hl-60 Cell Line., Edward D. Ball, Paul M. Guyre, Li Shen, John M. Glynn, Charles R. Maliszewski, Paul E. Baker, Michael W. Fanger
Gamma Interferon Induces Monocytoid Differentiation In The Hl-60 Cell Line., Edward D. Ball, Paul M. Guyre, Li Shen, John M. Glynn, Charles R. Maliszewski, Paul E. Baker, Michael W. Fanger
Dartmouth Scholarship
We investigated the ability of purified, recombinant DNA-derived interferons (IFN) to induce phenotypic changes in cells of the HL-60 promyelocytic leukemia cell line. Changes in cell surface markers detected by monoclonal antibodies as well as morphologic, histochemical, and functional changes were monitored. We found that gamma-IFN, but not alpha- or beta-IFN, induced the expression of antigens characteristic of monocytes and granulocytes (AML-2-23, 63D3, and 61D3), as well as changes in morphology consistent with monocytoid differentiation. These included induction of alpha-naphthyl acetate esterase, increased cell size, and a decrease in azurophilic granules. The gamma-IFN dose dependency and time course of the …
Triggering Of The T3-Ti Antigen-Receptor Complex Results In Clonal T-Cell Proliferation Through An Interleukin 2-Dependent Autocrine Pathway., Stefan C. Meuer, Rebecca E. Hussey, Doreen A. Cantrell, James C. Hodgdon, Stuart F. Schlossman, Kendall A. Smith, Ellis L. Reinherz
Triggering Of The T3-Ti Antigen-Receptor Complex Results In Clonal T-Cell Proliferation Through An Interleukin 2-Dependent Autocrine Pathway., Stefan C. Meuer, Rebecca E. Hussey, Doreen A. Cantrell, James C. Hodgdon, Stuart F. Schlossman, Kendall A. Smith, Ellis L. Reinherz
Dartmouth Scholarship
Human T-cell clones and anti-T-cell-receptor antibodies (clonotypic) directed at surface receptors for antigen (T3-Ti molecular complex) as well as anti-interleukin 2 (IL-2) and anti-IL-2-receptor antibodies were utilized to investigate the mechanism by which alloantigens or antigen plus self-major histocompatibility complex (MHC) (i.e., physiologic ligand) trigger specific clonal proliferation. Soluble or Sepharose-bound anti-Ti monoclonal antibodies, like physiologic ligand, enhanced proliferative responses to purified IL-2 by inducing a 6-fold increase in surface IL-2 receptor expression. In contrast, only Sepharose-bound anti-Ti or physiologic ligand triggered endogenous clonal IL-2 production and resulted in subsequent proliferation. The latter was blocked by antibodies directed at either …
Interferon Gamma Blocks The Growth Of Toxoplasma Gondii In Human Fibroblasts By Inducing The Host Cells To Degrade Tryptophan., E. R. Pfefferkorn
Interferon Gamma Blocks The Growth Of Toxoplasma Gondii In Human Fibroblasts By Inducing The Host Cells To Degrade Tryptophan., E. R. Pfefferkorn
Dartmouth Scholarship
Treatment of human fibroblasts with human recombinant gamma interferon blocked the growth of Toxoplasma gondii, an obligate intracellular protozoan parasite. Growth of the parasite was measured by a plaque assay 7 days after infection or by the incorporation of [3H]uracil 1 or 2 days after infection. The antitoxoplasma activity induced in the host cells by gamma interferon was strongly dependent upon the tryptophan concentration of the medium. Progressively higher minimal inhibitory concentrations of gamma interferon were observed as the tryptophan concentration in the culture medium was increased. Treatment with gamma interferon did not make the cells impermeable to tryptophan. The …