CMVpp65-Specific T cells generated from naïve T cell populations recognize atypical but not canonical epitopes and may be protective in Vivo

UV radiation resistance-associated gene (UVRAG) encodes a tumor suppressor with putative roles in autophagy, endocytic trafficking, and DNA damage repair but its in vivo role in T cells is unknown. Because conditional homozygous deletion of Uvrag in mice results in early embryonic lethality, we generated T-cell–specific UVRAG-deficient mice that lacked UVRAG expression specifically in T cells. This loss of UVRAG led to defects in peripheral homeostasis that could not be explained by the increased sensitivity to cell death and impaired proliferation observed for other autophagy-related gene knockout mice. Instead, UVRAG-deficient T-cells exhibited normal mitochondrial clearance and activation-induced autophagy, suggesting that UVRAG has an autophagy-independent role that is critical for peripheral naive T-cell homeostatic proliferation. In vivo, T-cell–specific loss of UVRAG dampened CD8+ T-cell responses to LCMV infection in mice, delayed viral clearance, and impaired memory T-cell generation. Our data provide novel insights into the control of autophagy in T cells and identify UVRAG as a new regulator of naïve peripheral T-cell homeostasis.

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Antigen-Experienced CD4+ T Cells Limit Naïve T-Cell Priming in Response to Therapeutic Vaccination In vivo

Cancer Research ◽

10.1158/0008-5472.can-09-4398 ◽

2010 ◽

Vol 70 (15) ◽

pp. 6161-6170 ◽

Cited By ~ 4

Author(s):

Chris Schiering ◽

Jlenia Guarnerio ◽

Veronica Basso ◽

Luca Muzio ◽

Anna Mondino

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Therapeutic Vaccination ◽

T Cell Priming ◽

Naïve T Cell ◽

Naive T Cell

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VISTA is a checkpoint regulator for naïve T cell quiescence and peripheral tolerance

Science ◽

10.1126/science.aay0524 ◽

2020 ◽

Vol 367 (6475) ◽

pp. eaay0524 ◽

Cited By ~ 22

Author(s):

Mohamed A. ElTanbouly ◽

Yanding Zhao ◽

Elizabeth Nowak ◽

Jiannan Li ◽

Evelien Schaafsma ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Activation ◽

Cell Subset ◽

Peripheral Tolerance ◽

Cell Immune Response ◽

Naive T Cells ◽

Naïve T Cells ◽

Naïve T Cell ◽

Naive T Cell

Negative checkpoint regulators (NCRs) temper the T cell immune response to self-antigens and limit the development of autoimmunity. Unlike all other NCRs that are expressed on activated T lymphocytes, V-type immunoglobulin domain-containing suppressor of T cell activation (VISTA) is expressed on naïve T cells. We report an unexpected heterogeneity within the naïve T cell compartment in mice, where loss of VISTA disrupted the major quiescent naïve T cell subset and enhanced self-reactivity. Agonistic VISTA engagement increased T cell tolerance by promoting antigen-induced peripheral T cell deletion. Although a critical player in naïve T cell homeostasis, the ability of VISTA to restrain naïve T cell responses was lost under inflammatory conditions. VISTA is therefore a distinctive NCR of naïve T cells that is critical for steady-state maintenance of quiescence and peripheral tolerance.

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The lymphoid chemokine CCL21 costimulates naïve T cell expansion and Th1 polarization of non-regulatory CD4+ T cells

Cellular Immunology ◽

10.1016/j.cellimm.2004.12.006 ◽

2004 ◽

Vol 231 (1-2) ◽

pp. 75-84 ◽

Cited By ~ 75

Author(s):

Kenneth Flanagan ◽

Dorota Moroziewicz ◽

Heesun Kwak ◽

Heidi Hörig ◽

Howard L. Kaufman

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Cell Expansion ◽

T Cell Expansion ◽

Th1 Polarization ◽

Naïve T Cell ◽

Naive T Cell

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Naive T-cell receptor transgenic T cells help memory B cells produce antibody

Immunology ◽

10.1111/j.1365-2567.2006.02446.x ◽

2006 ◽

Vol 119 (3) ◽

pp. 376-384 ◽

Cited By ~ 9

Author(s):

Darragh Duffy ◽

Chun-Ping Yang ◽

Andrew Heath ◽

Paul Garside ◽

Eric B. Bell

Keyword(s):

T Cells ◽

T Cell ◽

B Cells ◽

T Cell Receptor ◽

Cell Receptor ◽

Memory B Cells ◽

Naïve T Cell ◽

Naive T Cell

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Interleukin-7–treated naive T cells can be productively infected by T-cell–adapted and primary isolates of human immunodeficiency virus 1

Blood ◽

10.1182/blood.v99.9.3310 ◽

2002 ◽

Vol 99 (9) ◽

pp. 3310-3318 ◽

Cited By ~ 56

Author(s):

Carolyn M. Steffens ◽

Elizabeth Z. Managlia ◽

Alan Landay ◽

Lena Al-Harthi

Keyword(s):

Human Immunodeficiency Virus ◽

T Cells ◽

T Cell ◽

Productive Infection ◽

Naive T Cells ◽

Naïve T Cells ◽

Interleukin 7 ◽

Immunodeficiency Virus ◽

Naïve T Cell ◽

Naive T Cell

Abstract Although human immunodeficiency virus (HIV)gag/pol DNA can be detected in naive T cells, whether naive T cells can be productively infected by HIV is still questionable. Given that interleukin-7 (IL-7) is a prospective therapeutic immunomodulator for the treatment of HIV, we evaluated the effect of IL-7 on promoting naive T-cell infection of laboratory-adapted (IIIB), M-tropic, and primary isolates of HIV. Initially, we determined that the 3 cell surface markers widely used to identify naive T cells (CD45RA+CD45RO−, CD45RA+CD62L+, and CD45RO−CD27+CD95low) are all equivalent in T-cell receptor excision circle content, a marker for the replicative history of a cell as well as for de novo T cells. We therefore used CD45RA+CD45RO− expression to define naive T cells in this study. We demonstrate that although untreated or IL-2–treated naive T cells are not productively infected by HIV, IL-7 pretreatment mediated the productive infection of laboratory-adapted, M-tropic, and primary isolates of HIV as determined by p24 core antigen production. This up-regulation was between 8- and 58-fold, depending on the HIV isolate used. IL-7 pretreatment of naive T cells also potently up-regulated surface expression of CXCR4 but not CCR5 and mediated the expansion of naive T cells without the acquisition of the primed CD45RO phenotype. Collectively, these data indicate that IL-7 augments naive T-cell susceptibility to HIV and that under the appropriate environmental milieu, naive T cells may be a source of HIV productive infection. This information needs to be considered in evaluating IL-7 as an immunomodulator for HIV-infected patients.

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Ex Vivo Fludarabine Selectively Depletes Human Naive T-Cell Subsets: A Step Toward Modifying Donor Lymphocyte Infusion.

Blood ◽

10.1182/blood.v106.11.1071.1071 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1071-1071

Author(s):

Melody M. Smith ◽

Cynthia R. Giver ◽

Edmund K. Waller ◽

Christopher R. Flowers

Keyword(s):

T Cells ◽

T Cell ◽

Cd8 T Cells ◽

Cd4 T Cells ◽

Memory T Cells ◽

Ex Vivo ◽

T Cell Subsets ◽

Effector Memory ◽

Naïve T Cell ◽

Naive T Cell

Abstract Ex vivo modification of donor lymphocytes with purine analogs (mDL) may help to minimize graft versus host disease (GvHD) while providing beneficial graft versus leukemia (GvL) effects. In a murine model system, we have shown that allogeneic donor splenocytes, treated with fludarabine ex vivo have significantly reduced GvHD activity when transferred to irradiated recipient mice, and retain anti-viral and GvL activities (Giver, 2003). This effect appears to be mediated by relative depletion of donor CD4 CD44low, “naive” T-cells. As a first step toward developing mDL for use in patients, we sought to evaluate the effects of ex vivo fludarabine exposure on human T-cell subsets, and to determine the minimum dose of fludarabine required to achieve this effect. Methods: Peripheral blood mononuclear cell samples from 6 healthy volunteers were evaluated at 0, 24, 48, and 72 hour time points after ex vivo incubation in varying dosages of fludarabine: 2, 5, and 10(n=3) mcg/ml. Fludarabine incubated samples were compared to samples that received no fludarabine (untreated). The total viable cell number was determined and the fractions and absolute numbers of viable CD4 and CD8 naïve and memory T-cells were determined using flow cytometry after incubation with 7-AAD (dead cell stain), CD4, CD8, CD45RA, CD62L, and CCR7 antibodies, and measuring the total viable cells/ml. Results: The numbers of viable CD4 and CD8 T-cells remained relatively stable in control cultures. Without fludarabine, the average viability at 72 hr of naive and memory T-cells were 92% and 77% for CD4 and 86% and 63% for CD 8 (Fig. 1A). Naive CD4 T-cells were more sensitive to fludarabine-induced death than memory CD4 cells. At 72 hr, the average viability of fludarabine-treated naive CD4 T-cells was 33% at 2 mcg/ml (8.2X the reduction observed in untreated cells) and 30% at 5 mcg/ml, while memory CD4 T-cells averaged 47% viability at 2 mcg/ml (2.3X the reduction observed in untreated cells) (Fig. 1B) and 38% at 5 mcg/ml. The average viability of naive CD8 T-cells at 72 hr was 27% at 2 mcg/ml and 20% at 5 mcg/ml, while memory CD8 T-cell viability was 22% at 2 mcg/ml and 17% at 5 mcg/ml. Analyses on central memory, effector memory, and Temra T-cells, and B-cell and dendritic cell subsets are ongoing. The 5 and 10 mcg/ml doses also yielded similar results in 3 initial subjects, suggesting that 2 mcg/ml or a lower dose of fludarabine is sufficient to achieve relative depletion of the naive T-cell subset. Conclusions: Future work will determine the minimal dose of fludarabine to achieve this effect, test the feasibility of using ex vivo nucleoside analog incubation to reduce alloreactivity in samples from patient/donor pairs, and determine the maximum tolerated dose of mDL in a phase 1 clinical trial with patients at high risk for relapse and infectious complications following allogeneic transplantation. Figure Figure

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Alemtuzumab Treatment Can Affect CD52 Positive As Well As CD52 Negative GPI-Deficient, Sezary Cells Allowing Long-Term Disease Control

Blood ◽

10.1182/blood.v118.21.2491.2491 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2491-2491

Author(s):

C.J.M. Halkes ◽

I Jedema ◽

H.M. van Egmond ◽

L van der Fits ◽

J.H.F. Falkenburg ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Fold Increase ◽

Cell Populations ◽

Proliferative Potential ◽

Small Populations ◽

Collateral Damage ◽

Sézary Cells

Abstract Abstract 2491 Alemtuzumab (ALT) is a monoclonal anti CD52 antibody used for the treatment of CD52 positive lymphoid malignancies and to deplete T cells in vivo and in vitro to prevent graft rejection or GVHD after allogeneic stem cell transplantation (alloSCT). Membrane CD52 expression depends on the presence of a glycosylphosphatidylinositol (GPI) anchor. GPI deficiency is frequently found in small populations of normal and malignant hematopoietic cells, including T and B cells (frequencies from <0.01 to 2%). These cells lack expression of GPI-linked proteins like CD52 as can be detected by absence of staining of FLAER, which is an aerolysin that specifically binds to mammalian GPI anchors. After alloSCT using ALT for T cell depletion, reconstitution of FLAER and CD52 double negative cells is seen, and outgrowth of CD52 negative malignant cell populations has been found after single agent treatment with ALT in malignant diseases. However, GPI deficient cells have been suggested to have a lower proliferative potential and a decreased survival due to their increased susceptibility to spontaneous complement mediated cell lysis, possibly explaining the infrequent dominant outgrowth of GPI deficient clones in healthy individuals. Sézary Syndrome (SS) is an aggressive cutaneous T cell lymphoma characterized by the presence of high numbers of neoplastic T cells expressing CD4 and CD52 in peripheral blood, lymph nodes and skin. Clinical responses in SS patients after single drug treatment with low dosed ALT have been described by several investigators. However, in 6 out of 6 patients analyzed, we found a small population of CD52 and FLAER negative Sézary cells, illustrating that a GPI negative subpopulation is frequently observed which may lead to outgrowth of CD52 negative Sézary cells. We treated 3 patients with successive courses of low dose ALT (10 mg subcutaneously once weekly until circulating malignant cells were < 1,000/mm3) and followed the kinetics of CD52- and CD52+ Sézary cells. Before ALT treatment, a CD4+CD52-FLAER- T cell population was found in all three patients (0.01–0.06% of all circulating CD4+ T cells). As expected, a rapid decrease in absolute numbers of CD4+CD52+FLAER+ cells was observed after ALT treatment (decrease 94 to 100%). Surprisingly, despite the absence of the CD52 target molecule, the absolute number of CD4+CD52-FLAER- T cells also decreased after the first and second treatment cycles in all three patients (decreases between 22 and 96%), indicating that the massive in vivo ALT mediated lysis of CD52+ Sézary cells coincided with collateral damage of CD52- Sézary cells. Between successive treatment courses in the absence of circulating ALT, the absolute numbers of CD4+CD52+FLAER+ T cells showed a more rapid increase compared to CD4+CD52-FLAER- T cells in all patients (median 193 fold increase (range 17–896) versus 9 fold increase (range 2–144) respectively), illustrating a decreased in vivo proliferative potential of these GPI negative cells. After repeated doses of ALT, one of the patients developed resistance to ALT treatment. Phenotype analysis revealed that 97% of the 23,000/mm3 circulating Sézary cells were CD4+CD52-FLAER-. Clonality analysis showed that CD4+CD52+FLAER+ and CD4+CD52-FLAER–Sézary cell populations expressed identical T cell receptor V-beta chains demonstrating that both cell populations are part of the same initial clone of Sézary cells. At present, one year after the start of ALT treatment, reponses are still observed in both other patients without overgrowth of a CD4+CD52-FLAER–Sézary cells. We conclude that despite presence of small populations of CD52 and GPI negative cells in patients with Sézary Syndrome, all patients respond to treatment with alemtuzumab. CD52 negative, GPI deficient Sézary cells showed high susceptibility to collateral damage during antibody treatment. During treatment intervals, CD52+ cells showed a faster recovery compared to CD52- cells, indicating a lower proliferative potential of the GPI deficient Sézary cells. Although, as shown in one patient, ultimate outgrowth of GPI deficient CD52- sezary cells can occur, the capacity to achieve long term control of both CD52+ and CD52- Sézary cells in several patients offers a rationale for treatment of SS with alemtuzumab, possibly in combination with a low dosed cytotoxic drug Disclosures: Off Label Use: Alemtuzumab for treatment of Sezary Syndrome.

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