scholarly journals Lipocortin 1 binding sites on human T-cells: The population of cells with the binding sites is larger in CD8 T-lymphocytes than in CD4 T-lymphocytes

IUBMB Life ◽  
1996 ◽  
Vol 40 (6) ◽  
pp. 1167-1173
Author(s):  
Ha Won Kim ◽  
Euna Choi ◽  
Bin Yoo ◽  
Jung Ryul Choi ◽  
Young Min Park ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Binding Sites ◽  
Cd8 T Lymphocytes ◽  
Human T Cells

scholarly journals Circulating CD8 T Lymphocytes in Human Immunodeficiency Virus-Infected Individuals Have Impaired Function and Downmodulate CD3ζ, the Signaling Chain of the T-Cell Receptor Complex

Blood ◽  
1998 ◽  
Vol 91 (2) ◽  
pp. 585-594 ◽  
Author(s):  
Linda A. Trimble ◽  
Judy Lieberman
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Receptor Complex ◽  
Cd8 T Lymphocytes ◽  
Immunodeficiency Virus ◽  
Specific Cytotoxicity

Although human immunodeficiency virus (HIV)-infected subjects without acquired immunodeficiency syndrome have a high frequency of HIV-specific CD8 T lymphocytes, freshly isolated lymphocytes frequently lack detectable HIV-specific cytotoxicity. However, this effector function becomes readily apparent after overnight culture. To investigate reasons for T-cell dysfunction, we analyzed T-cell expression of the cytolytic protease granzyme A and of CD3ζ, the signaling component of the T-cell receptor complex. An increased proportion of CD4 and CD8 T cells from HIV-infected donors contain granzyme A, consistent with the known increased frequency of activated T cells. In 28 HIV-infected donors with mild to advanced immunodeficiency, a substantial fraction of circulating T cells downmodulated CD3ζ (fraction of T cells expressing CD3ζ, 0.74 ± 0.16 v 1.01 ± 0.07 in healthy donors; P < .0000005). CD3ζ expression is downregulated more severely in CD8 than CD4 T cells, decreases early in infection, and correlates with declining CD4 counts and disease stage. CD3ζ expression increases over 6 to 16 hours of culture in an interleukin-2–dependent manner, coincident with restoration of viral-specific cytotoxicity. Impaired T-cell receptor signaling may help explain why HIV-specific cytotoxic T lymphocytes fail to control HIV replication.

Interferon- Activates Multiple STAT Proteins and Upregulates Proliferation-Associated IL-2R, c-myc, and pim-1 Genes in Human T Cells

Blood ◽  
1999 ◽  
Vol 93 (6) ◽  
pp. 1980-1991 ◽  
Author(s):  
Sampsa Matikainen ◽  
Timo Sareneva ◽  
Tapani Ronni ◽  
Anne Lehtonen ◽  
Päivi J. Koskinen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Cell Biology ◽  
Interleukin 2 ◽  
T Cell Proliferation ◽  
Stat Proteins ◽  
Human T Cells ◽  
T Cell Biology ◽  
Cytokine Stimulation

Interferon- (IFN-) is a pleiotropic cytokine that has antiviral, antiproliferative, and immunoregulatory functions. There is increasing evidence that IFN- has an important role in T-cell biology. We have analyzed the expression ofIL-2R, c-myc, and pim-1 genes in anti-CD3–activated human T lymphocytes. The induction of these genes is associated with interleukin-2 (IL-2)–induced T-cell proliferation. Treatment of T lymphocytes with IFN-, IL-2, IL-12, and IL-15 upregulated IL-2R, c-myc, andpim-1 gene expression. IFN- also sensitized T cells to IL-2–induced proliferation, further suggesting that IFN- may be involved in the regulation of T-cell mitogenesis. When we analyzed the nature of STAT proteins capable of binding to IL-2R,pim-1, and IRF-1 GAS elements after cytokine stimulation, we observed IFN-–induced binding of STAT1, STAT3, and STAT4, but not STAT5 to all of these elements. Yet, IFN- was able to activate binding of STAT5 to the high-affinity IFP53 GAS site. IFN- enhanced tyrosine phosphorylation of STAT1, STAT3, STAT4, STAT5a, and STAT5b. IL-12 induced STAT4 and IL-2 and IL-15 induced STAT5 binding to the GAS elements. Taken together, our results suggest that IFN-, IL-2, IL-12, and IL-15 have overlapping activities on human T cells. These findings thus emphasize the importance of IFN- as a T-cell regulatory cytokine.

Telomerase levels control the lifespan of human T lymphocytes

Blood ◽  
2003 ◽  
Vol 102 (3) ◽  
pp. 849-857 ◽  
Author(s):  
Alexander Röth ◽  
Hans Yssel ◽  
Jérôme Pène ◽  
Elizabeth A. Chavez ◽  
Mike Schertzer ◽  
...  
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Ectopic Expression ◽  
Dominant Negative ◽  
Major Influence ◽  
Telomeric Dna ◽  
Human Telomerase Reverse Transcriptase ◽  
Human T Lymphocytes ◽  
Human T Cells

Abstract The loss of telomeric DNA with each cell division contributes to the limited replicative lifespan of human T lymphocytes. Although telomerase is transiently expressed in T lymphocytes upon activation, it is insufficient to confer immortality. We have previously shown that immortalization of human CD8+ T lymphocytes can be achieved by ectopic expression of the human telomerase reverse transcriptase (hTERT) gene, which encodes for the catalytic component of the telomerase complex. To study the role of endogenous hTERT in the lifespan of human T cells, we blocked endogenous hTERT expression by ectopic expression of dominant-negative (DN) hTERT. Cells expressing DN-hTERT had a decreased lifespan and showed cytogenetic abnormalities, including chromosome ends without detectable telomeric DNA as well as chromosome fusions. These results indicate that while endogenous hTERT cannot prevent overall telomere shortening, it has a major influence on the longevity of human T cells. Furthermore, we show that up-regulation of hTERT in T cells upon activation decreases over time in culture. Long-term–cultured T cells also show a decreased expression of c-myc upon activation, resulting in less c-myc–induced transcription of hTERT. Moreover, memory T cells, which have expanded in vivo upon antigen encounter, expressed a lower level of hTERT upon activation than naive cells from the same donor. The observed inverse correlation between telomerase levels and replicative history suggests that telomerase levels in T cells are limiting and increasingly insufficient to sustain their proliferation.

scholarly journals Cytokine Signals Are Sufficient for HIV-1 Infection of Resting Human T Lymphocytes

1999 ◽  
Vol 189 (11) ◽  
pp. 1735-1746 ◽  
Author(s):  
Derya Unutmaz ◽  
Vineet N. KewalRamani ◽  
Shana Marmon ◽  
Dan R. Littman
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Structure Function ◽  
Human Lymphocytes ◽  
Stable Gene ◽  
Mutant Form ◽  
Primary Cells ◽  
Human T Cells ◽  
Transformed Cell Lines ◽  
Hiv 1

Lentiviral vectors have been advocated to be effective vehicles for the delivery and stable expression of genes in nondividing primary cells. However, certain cell types, such as resting T lymphocytes, are resistant to infection with HIV-1. Establishing parameters for stable gene delivery into primary human lymphocytes and approaches to overcome the resistance of resting T cells to HIV infection may permit potential gene therapy applications, genetic studies of primary cells in vitro, and a better understanding of the stages of the lentiviral life cycle. Here we demonstrate that an HIV-1–derived vector can be used for stable delivery of genes into activated human T cells as well as natural killer and dendritic cells. Remarkably, a sizeable fraction of resting T cells was stably transduced with the HIV-1 vector when cultured with the cytokine interleukin (IL)-2, IL-4, IL-7, or IL-15, or, at a lower level, with IL-6, in the absence of any other stimuli. Resting T cells stimulated with these cytokines could also be infected with replication-competent HIV-1. To test the utility of this system for performing structure–function analysis in primary T cells, we introduced wild-type as well as a mutant form of murine CD28 into human T cells and showed a requirement for the CD28 cytoplasmic domain in costimulatory signaling. The ability to stably express genes of interest in primary T cells will be a valuable tool for genetic and structure–function studies that previously have been limited to transformed cell lines. In addition, the finding that cytokine signals are sufficient to permit transduction of resting T cells with HIV may be relevant for understanding mechanism of HIV-1 transmission and pathogenesis.

scholarly journals Induction of a Novel Cellular Homolog of Interleukin-10, AK155, by Transformation of T Lymphocytes with Herpesvirus Saimiri

2000 ◽  
Vol 74 (8) ◽  
pp. 3881-3887 ◽  
Author(s):  
Andrea Knappe ◽  
Simon Hör ◽  
Sabine Wittmann ◽  
Helmut Fickenscher
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Subtractive Hybridization ◽  
Interleukin 10 ◽  
Herpesvirus Saimiri ◽  
Cell Functions ◽  
Human T Cells ◽  
Cellular Homolog ◽  
T Cell Lines

ABSTRACT Although herpesvirus saimiri-transformed T lymphocytes retain multiple normal T-cell functions, only a few changes have been described. By subtractive hybridization, we have isolated a novel cellular gene, ak155, a sequence homolog of the interleukin-10 gene. Specifically herpesvirus saimiri-transformed T cells overexpress ak155 and secrete the protein into the supernatant. In other T-cell lines and in native peripheral blood cells, but not in B cells, ak155 is transcribed at low levels. AK155 forms homodimers similarly to interleukin-10. As a lymphokine, AK155 may contribute to the transformed phenotype of human T cells after infection by herpesvirus saimiri.

scholarly journals Alterations in T-Cell Receptor Vβ Repertoire of CD4 and CD8 T Lymphocytes in Human Immunodeficiency Virus-Infected Children

2003 ◽  
Vol 10 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Monica Kharbanda ◽  
Thomas W. McCloskey ◽  
Rajendra Pahwa ◽  
Mei Sun ◽  
Savita Pahwa
Keyword(s):  
Human Immunodeficiency Virus ◽  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Receptor ◽  
Cd8 T Cells ◽  
Chronic Phase ◽  
Cell Receptor ◽  
Cd8 T Lymphocytes ◽  
Immunodeficiency Virus

ABSTRACT Perturbations in the T-cell receptor (TCR) Vβ repertoire were assessed in the CD4 and CD8 T lymphocytes of human immunodeficiency virus (HIV)-infected children who were receiving therapy during the chronic phase of infection by flow cytometry (FC) and PCR analysis. By FC, representation of 21 TCR Vβ subfamilies was assessed for an increased or decreased percentage in CD4 and CD8 T cells, and by PCR, 22 TCR Vβ subfamilies of CD4 and CD8 T cells were analyzed by CDR3 spectratyping for perturbations and reduction in the number of peaks, loss of Gaussian distribution, or clonal dominance. The majority of the TCR Vβ subfamilies were examined by both methods and assessed for deviation from the norm by comparison with cord blood samples. The CD8-T-lymphocyte population exhibited more perturbations than the CD4 subset, and clonal dominance was present exclusively in CD8 T cells. Of the 55 total CD8-TCR Vβ families classified with clonal dominance by CDR3 spectratyping, only 18 of these exhibited increased expression by FC. Patients with high numbers of CD8-TCR Vβ families with decreased percentages had reduced percentages of total CD4 T cells. Increases in the number of CD4-TCR Vβ families with increased percentages showed a positive correlation with skewing. Overall, changes from normal were often discordant between the two methods. This study suggests that the assessment of HIV-induced alterations in TCR Vβ families at cellular and molecular levels yields different information and that our understanding of the immune response to HIV is still evolving.

scholarly journals Simian immunodeficiency virus-specific cytotoxic T lymphocytes and cell-associated viral RNA levels in distinct lymphoid compartments of SIVmac-infected rhesus monkeys

Blood ◽  
2000 ◽  
Vol 96 (4) ◽  
pp. 1474-1479 ◽  
Author(s):  
Marcelo J. Kuroda ◽  
Jörn E. Schmitz ◽  
Aruna Seth ◽  
Ronald S. Veazey ◽  
Christine E. Nickerson ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Lymph Node ◽  
T Lymphocytes ◽  
Cytotoxic T Lymphocytes ◽  
Cd8 T Cells ◽  
Rhesus Monkeys ◽  
Cd8 T Lymphocytes ◽  
Tetramer Binding ◽  
Immunodeficiency Virus

Major histocompatibility class I–peptide tetramer technology and simian immunodeficiency virus of macaques (SIVmac)-infected rhesus monkeys were used to clarify the distribution of acquired immunodeficiency syndrome virus-specific cytotoxic T lymphocytes (CTL) in secondary lymphoid organs and to assess the relationship between these CTL and the extent of viral replication in the various anatomic compartments. SIVmac Gag epitope-specific CD8+ T cells were evaluated in the spleen, bone marrow, tonsils, thymus, and 5 different lymph node compartments of 4 SIVmac-infected rhesus monkeys. The average percentage of CD8+ T lymphocytes that bound this tetramer in all the different lymph node compartments was similar to that in peripheral blood lymphocytes in individual monkeys. The percentage of CD8+ T cells that bound the tetramer in the thymus was uniformly low in the monkeys. However, the percentage of CD8+ T cells that bound the tetramer in bone marrow and spleen was consistently higher than that seen in lymph nodes and peripheral blood. The phenotypic profile of the tetramer-binding CD8+ T lymphocytes in the different lymphoid compartments was similar, showing a high expression of activation-associated adhesion molecules and a low level expression of naive T-cell–associated molecules. Surprisingly, no correlation was evident between the percentage of tetramer-binding CD8+ T lymphocytes and the magnitude of the cell-associated SIV RNA level in each lymphoid compartment of individual monkeys. These studies suggest that a dynamic process of trafficking may obscure the tendency of CTL to localize in particular regional lymph nodes or that some lymphoid organs may provide milieus that are particularly conducive to CTL expansion.

scholarly journals Priming effects of granulocyte-macrophage colony-stimulating factor are coupled to cholera toxin-sensitive guanine nucleotide binding protein in human T lymphocytes

Blood ◽  
1994 ◽  
Vol 83 (5) ◽  
pp. 1299-1309
Author(s):  
A al-Aoukaty ◽  
A Giaid ◽  
C Sinoff ◽  
AD Ho ◽  
AA Maghazachi
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
G Protein ◽  
T Cell Proliferation ◽  
Gm Csf ◽  
Human T Cells ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

In addition to the mobilization of neutrophils and monocytes, granulocyte-macrophage colony-stimulating factor (GM-CSF) also mobilizes lymphocytes into peripheral blood. We examined the ability of GM-CSF to induce the proliferation of purified human T cells (CD3+ CD4+ CD56- CD16- B1- MO2-) in two major aspects: (1) the mechanisms of GM- CSF interaction with interleukin-2 (IL-2) causing T-cell proliferation, and (2) the intracellular signals transmitted by GM-CSF in T lymphocytes. We observed that concentrations of GM-CSF between 0.01 ng/mL and 10 ng/mL had a synergistic effect with concentrations of IL-2 between 1 U/mL and 10 U/mL in stimulating T-cell proliferation. This effect of GM-CSF was maximal when it was added at the start of the culture. In situ hybridization showed the presence of mRNA for GM-CSF receptors in T cells. Further analysis showed that GM-CSF induced the expression of IL-2 receptor (IL-2R) on the surface of T lymphocytes. These events coincide with the ability of GM-CSF to increase the intracellular levels of both cyclic 3′,5′-adenosine monophosphate (cAMP) and cyclic 3′,5′-guanosine monophosphate (cGMP) in T cells, to increase the binding of (gamma-35S) GTP to T-cell membranes, and to enhance GTPase activity as determined by increased hydrolysis of 32P- GTP. IL-2 also induced IL-2R expression, cyclic nucleotide secretion, and G-protein activation. However, the presence of IL-2 reduced GM-CSF induction of these activities. Addition of antibodies to the alpha and beta subunits of IL-2R permitted the activation of G protein by GM-CSF even when IL-2 was present. Furthermore, GTP binding and GTPase activity induced by GM-CSF or IL-2 were inhibited by the addition of cholera toxin (CT), but not pertussis toxin (PT). Cumulatively, these results suggest that in T lymphocytes, receptors for GM-CSF or IL-2 may be coupled to the same CT-sensitive G protein, although other possibilities may exist. The role that G proteins play in mediating the intracellular signaling pathways induced by GM-CSF or IL-2 in human T cells is supported by adenosine diphosphate-ribosylation of a 44-kD or a 39-kD G protein in T-cell membranes by CT and PT, respectively.

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