title: Monocytes from mobilized stem cells inhibit T cell function.
abstract: Granulocyte-macrophage colony-stimulating factor, mobilized peripheral blood stem cell (PSC) products, and peripheral blood leukocytes posttransplantation contain cells that cause allogeneic and autologous T cell apoptosis. Isolation and characterization of these cells demonstrated that they were low-density (Percoll fractionation) CD14+ monocytes. T cells in PSC products have a depressed phytohemagglutinin (PHA) mitogenic response; however, purified CD4+ or CD8+ T cells exhibit a statistically normal mitogenic function. Furthermore, no T cell inhibitory activity was observed in CD14+, CD4+, and CD8+ cell-depleted fractions enriched in CD4- CD8- TCR alpha/beta+ T cells. Inhibition of T cell function by CD14+ monocytes required cell-cell contact, and the analyses of DNA fragmentation by Southern and TUNEL analysis demonstrates an activation-induced T cell apoptosis in the presence of CD14+ monocytes. Reverse-transcriptase polymerase chain reaction studies suggested that high levels of interleukin-10 or tumor necrosis factor gene transcripts in the PSC products may contribute to the inhibition of T cell function.
authors.affiliation: Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha 68198-5660, USA.
authors.forename: K
authors.initials: K
authors.lastname: Ino
authors.forename: R K
authors.initials: RK
authors.lastname: Singh
authors.forename: J E
authors.initials: JE
authors.lastname: Talmadge
mesh_terms: D017209:Apoptosis / Q000502:physiology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D016207:Cytokines / Q000096:biosynthesis; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008213:Lymphocyte Activation / Q000187:drug effects; D010641:Phenotype; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*
chemical_list: D016207:Cytokines; D018950:Lipopolysaccharide Receptors; D010835:Phytohemagglutinins