Biological Characteristics of T Cells from CD4 Idiopathic Lymphocytopenia Patients Activated and Expanded Using Xcellerate™ Technology.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3834-3834
Author(s):  
Joy Lawrence ◽  
Mark L. Bonyhadi ◽  
Charlotte Cunningham-Rundles ◽  
Ronald J. Berenson ◽  
Alice Long
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Expansion ◽  
Cd4 T Cell ◽  
Similar Process ◽  
Surface Activation ◽  
Activation Marker ◽  
Cell Counts ◽  
Marker Expression ◽  
Very High

Abstract Idiopathic CD4 lymphocytopenia (ICL) is characterized by reduced CD4+ T cell counts in the absence of HIV infection or other defined causes. Patients with ICL generally have CD4+ T cell counts < 100/μL and are at risk for infections. Administration of IL-2 has been reported to reduce the risk of infections in some patients, but CD4+ T cell counts remain low. Currently, there is no available therapy to increase the number of CD4+ T cells in these patients. We have developed the Xcellerate™ Technology, in which T cells are activated and expanded ex vivo from peripheral blood mononuclear cells (PBMC) using microscopic paramagnetic beads conjugated with anti-CD3 and anti-CD28 monoclonal antibodies (Xcyte™Dynabeads®). In patients with low CD4 counts due to HIV or cancer chemotherapy, administration of T cells activated and expanded using the Xcellerate Technology or similar process leads to significant increases in CD4+ T cell counts to normal levels that are sustained over several months. In the current study, we tested the ability of the Xcellerate Technology to expand T cells from patients with ICL. We collected data on T cell phenotype, cell expansion, activation marker expression, cytokine secretion, T cell receptor (TCR) repertoire diversity, functional potential and response to restimulation. T cells expanded a median of 902 fold (range 281–1529; n=3 patients), and demonstrated typical induction of surface-activation marker expression, including upregulation of CD25 (IL-2R) and CD154 (CD40L). Phenotypic compositions of the ICL donor PBMC were heterogenous both before and after T cell expansion. Two patients had very high levels of CD4−CD8− T cells, and one of these two patients also had very high levels of γδ+ T cells. Each of these populations was maintained throughout expansion. The other patient displayed high levels of circulating CD3+CD56+ NKT cells that did not proliferate as robustly as other T cells during the expansion process. For two patients, flow cytometric analysis revealed a normal pattern of TCR Vβ surface expression while the remaining tissue had a skewed TCR Vβ distribution pattern. Following initial expansion and subsequent restimulation, T cells rapidly re-expressed surface activation markers and cytokines. In these preliminary studies, T cells from patients with ICL were expanded successfully using the Xcellerate Technology, suggesting that this approach might be used for clinical application in this disease.

scholarly journals PIMATM point-of-care testing for CD4 counts in predicting antiretroviral initiation in HIV-infected individuals in KwaZulu-Natal, Durban, South Africa

2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Mandisa Skhosana ◽  
Shabashini Reddy ◽  
Tarylee Reddy ◽  
Siphelele Ntoyanto ◽  
Elizabeth Spooner ◽  
...  
Keyword(s):  
South Africa ◽  
T Cells ◽  
T Cell ◽  
Antiretroviral Therapy ◽  
Cell Count ◽  
Point Of Care ◽  
Cd4 T Cell ◽  
Cell Counts ◽  
Kwazulu Natal ◽  
Cd4 T Cell Count

Introduction: Limited information is available on the usefulness of the PIMATM analyser in predicting antiretroviral treatment eligibility and outcome in a primary healthcare clinic setting in disadvantaged communities in KwaZulu-Natal, South Africa.Materials and methods: The study was conducted under the eThekwini Health Unit, Durban, KwaZulu-Natal. Comparison of the enumeration of CD4+ T-cells in 268 patients using the PIMATM analyser and the predicate National Health Laboratory Services (NHLS) was undertaken during January to July 2013. Bland-Altman analysis to calculate bias and limits of agreement, precision and levels of clinical misclassification at various CD4+ T-cell count thresholds was performed.Results: There was high precision of the PIMATM control bead cartridges with low and normal CD4+ T-cell counts using three different PIMATM analysers (%CV < 5). Under World Health Organization (WHO) guidelines (≤ 500 cells/mm3), the sensitivity of the PIMATM analyser was 94%, specificity 78% and positive predictive value (PPV) 95%. There were 24 (9%) misclassifications, of which 13 were false-negative in whom the mean bias was 149 CD4+ T-cells/mm3. Most (87%) patients returned for their CD4 test result but only 67% (110/164) of those eligible (≤ 350 cells/mm3) were initiated on antiretroviral therapy (ART) with a time to treatment of 49 days (interquartile range [IQR], 42–64 days).Conclusion: There was adequate agreement between PIMATM analyser and predicate NHLS CD4+ T-cell count enumeration (≤ 500 cells/mm3) in adult HIV-positive individuals. The high PPV, sensitivity and acceptable specificity of the PIMATM analyser technology lend it as a reliable tool in predicting eligibility and rapid linkage to care in ART programmes.Keywords: HIV; Point of Care; PIMATM CD4+ T cell counts; antiretroviral therapy; prediction/eligibility; South Africa

scholarly journals Brain cancer induces systemic immunosuppression through release of non-steroid soluble mediators

Brain ◽  
2020 ◽  
Author(s):  
Katayoun Ayasoufi ◽  
Christian K Pfaller ◽  
Laura Evgin ◽  
Roman H Khadka ◽  
Zachariah P Tritz ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Brain Cancer ◽  
Cd4 T Cell ◽  
Complex Class ◽  
Thymic Involution ◽  
Cell Counts ◽  
Histocompatibility Complex ◽  
Hallmark Feature

Abstract Immunosuppression of unknown aetiology is a hallmark feature of glioblastoma and is characterized by decreased CD4 T-cell counts and downregulation of major histocompatibility complex class II expression on peripheral blood monocytes in patients. This immunosuppression is a critical barrier to the successful development of immunotherapies for glioblastoma. We recapitulated the immunosuppression observed in glioblastoma patients in the C57BL/6 mouse and investigated the aetiology of low CD4 T-cell counts. We determined that thymic involution was a hallmark feature of immunosuppression in three distinct models of brain cancer, including mice harbouring GL261 glioma, B16 melanoma, and in a spontaneous model of diffuse intrinsic pontine glioma. In addition to thymic involution, we determined that tumour growth in the brain induced significant splenic involution, reductions in peripheral T cells, reduced MHC II expression on blood leucocytes, and a modest increase in bone marrow resident CD4 T cells. Using parabiosis we report that thymic involution, declines in peripheral T-cell counts, and reduced major histocompatibility complex class II expression levels were mediated through circulating blood-derived factors. Conversely, T-cell sequestration in the bone marrow was not governed through circulating factors. Serum isolated from glioma-bearing mice potently inhibited proliferation and functions of T cells both in vitro and in vivo. Interestingly, the factor responsible for immunosuppression in serum is non-steroidal and of high molecular weight. Through further analysis of neurological disease models, we determined that the immunosuppression was not unique to cancer itself, but rather occurs in response to brain injury. Non-cancerous acute neurological insults also induced significant thymic involution and rendered serum immunosuppressive. Both thymic involution and serum-derived immunosuppression were reversible upon clearance of brain insults. These findings demonstrate that brain cancers cause multifaceted immunosuppression and pinpoint circulating factors as a target of intervention to restore immunity.

Immunoregulatory T Cells May Be Involved in Preserving CD4 T Cell Counts in HIV-Infected Long-Term Nonprogressors and Controllers

2014 ◽  
Vol 65 (1) ◽  
pp. 10-18 ◽  
Author(s):  
Julie C. Gaardbo ◽  
Andreas Ronit ◽  
Hans J. Hartling ◽  
Lise M. R. Gjerdrum ◽  
Karoline Springborg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cell ◽  
Cell Counts ◽  
Immunoregulatory T Cells

CD26+CD4+T cell counts and attack risk in interferon-treated multiple sclerosis

2005 ◽  
Vol 11 (6) ◽  
pp. 641-645 ◽  
Author(s):  
F Sellebjerg ◽  
C Ross ◽  
N Koch-Henriksen ◽  
P Soelberg Sørensen ◽  
J L Frederiksen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Hazard Ratio ◽  
Cd4 T Cell ◽  
Immunomodulatory Treatment ◽  
Cell Counts ◽  
Increased Risk ◽  
Insufficient Response

Biomarkers that allow the identification of patients with multiple sclerosis (MS) with an insufficient response to immunomodulatory treatment would be desirable, as currently available treatments are only incompletely efficacious. Previous studies have shown that the expression of CD25, CD26 and CCR5 on T cells is altered in patients with active MS. We studied the expression of these molecules by flow cytometry in patients followed for six months during immunomodulatory treatment. In interferon (IFN)-β-treated patients, we found that the hazard ratio for developing an attack was 2.8 in patients with CD26+CD4+T cell counts above median, and this risk was independent of the risk conferred by neutralizing anti-IFN-β antibodies. CD26+CD4+T cell counts may identify patients with MS at increased risk of attack during treatment with IFN-β.

Feasibility of a Stem Cell Gene Therapy Approach with Nonmyeloablative Conditioning in Patients with HIV-1 Infection.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 412-412
Author(s):  
Gian-Paolo Rizzardi ◽  
Silvia Nozza ◽  
Lucia Turchetto ◽  
Alexandre Harari ◽  
Giuseppe Tambussi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cell ◽  
Cell Counts ◽  
Cd34 Cells ◽  
Ifn Γ ◽  
Cell Gene ◽  
Stem Cell Gene ◽  
Hiv 1

Abstract Several reasons warrant the development of innovative therapeutic strategies for HIV/AIDS. These include the inability of highly active antiretroviral therapy (HAART) to eradicate the virus, the HAART-induced severe long-term toxicity occurring in patients, the development of HAART-resistant HIV-1 strains in the host, and the lack of an efficacious vaccine. Genetic engineering of hematopoietic stem cells (HSC) combined with nonmyeloablative conditioning proved safety and efficacy in the treatment of adenosine deaminase-deficient severe combined immunodeficiency. The feasibility of such an approach in HIV-1 infection remains, however, to be determined. In an open-label prospective trial, 18 patients with HIV-1 infection (mean±SE age 35.7±1.2, range 18.9–40; HAART since at least 3 months; CD4+ T cell counts &gt;200/μl) have been enrolled in a HSC retroviral vector gene therapy trial using RevM10 and polAS as anti-HIV genes. Nine patients received fresh transduced CD34+ cells and all study treatments, including CD34+ cell mobilisation with G-CSF (10 μg/kg/day for 5 days), CD34+ cell collection through aphaeresis, and nonmyeloablative conditioning (1.8 g/m2 cyclophosphamide [CY]), while 9 did not undergo all study phases. All patients have been followed-up for at least 48 weeks. Mean±SE baseline CD4+ T cell counts were 577±42, while plasma HIV-1 RNA levels (VL) were below the limit of detection (80 copies/ml) of the assay (Nasba Organon) in 9 out of 18 patients. CD34+ cells were efficiently mobilized and collected from patients with HIV-1 infection, achieving 4.42±0.64 x 106 CD34+ cells/kg after purification (CliniMACS, Miltenyi Biotec), and 3.93±1.2 x 106 viable CD34+ cells/kg in the infusion product, 30% of which were transduced CD34+ cells. It is worth noting that 1) effective VL suppression significantly increased the yields of mobilization, purification and transduction processes, and 2) peripheral blood CD34+ cell counts before aphaeresis (mean, 72 cells/μl) predicted the number of viable CD34+ cells infused (β 0.722, 95% CI 0.007–0.092, P=0.028, regression analysis), and a cut-off value &gt;30 CD34+ cells/μl predicted the success of all procedures (P=0.018, χ2 analysis, Fisher’s exact test). Gene marking levels, predicted by the number of transduced cells infused, were detectable in all patients, though they significantly decreased over time. CY conditioning caused a marked decrease in CD4+ T cell counts, restored over long-term follow-up. This recovery correlated with levels of CD4+ TCR-rearrangement excision circles and CD4+CD45RA+CCR7+ naïve T cells, indicating thymus regeneration capacity in &gt;30-year-old patients with HIV-1 infection. Importantly, CMV-specific IL-2- and IFN- γ-secreting CD4+CD69+ T cells were able to expand while no clinically relevant CMV reactivation occurred; moreover, proportions of IL-2, IL-2/IFN- γ, and IFN-γ-secreting HSV, TT, and EBV-specific CD4+ T cells were not altered by CY over time. These data indicate that effective stem cell gene transfer is feasible in patients with HIV-1 infection, and suggest the use of non-lymphocyte-toxic conditioning regimen, such as busulfan.

T Cell Responses during Long-Term Continuous Infusion of MT103 (MEDI-538; Anti-CD19 BiTE) in Patients with Relapsed B-NHL: Data from Dose-Escalation Study MT103-104.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2725-2725 ◽  
Author(s):  
Matthias Klinger ◽  
Peter Kufer ◽  
Petra Kirchinger ◽  
Ralf Lutterbüse ◽  
Eugen Leo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Dose Escalation ◽  
Cell Expansion ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Cell Counts ◽  
T Cell Expansion

Abstract MT103 (MEDI-538) is a bispecific single-chain antibody construct directed at CD3 on human T cells and CD19 on human B lymphoma and normal B cells. Transient linkage of B and T cells by MT103 provides T cells with a T cell receptor (TCR)-like signal leading to redirected lysis of B cell targets without apparent need of costimulation and inducing T cells to proliferate, secrete cytokines and upregulate surface activation markers. TCR-like signalling by MT103 is strictly dependent on the presence of target cells. Redirected lysis of CD19-positive cells by MT103 is seen at low picomolar concentrations and at low effector-to-target ratios. The in-vivo half-life of MT103 is approximately two hours. In the ongoing dose escalation study MT103-104, patients with relapsed B-NHL have so far received continuous infusion of MT103 at maintenance flow-rates of 0.5, 1.5, 5 and 15 μg/m2/24h for 4 or 8 weeks following a 3+3 dose escalation design. Serum concentrations of MT103 remained constant over the entire treatment period at a level depending on the respective maintenance flow-rate. Depletion of circulating B (lymphoma) cells could be observed more frequently with increasing dose levels (DL) from DL1 to DL3, and in all evaluable patients at DL4. Three of six evaluable patients at DL4 showed clinical responses (2 PR, 1 CR) according to standardized Cheson criteria, but no patient of DL1-3. The time courses of absolute CD4 and CD8 T cell counts in peripheral blood were determined by flow cytometry. CD8 T lymphocytes were further subdivided for analysis into naïve T cells, TCM (central memory T cells), TEM (effector memory T cells) and TEMRA (non-proliferating terminally differentiated CTL), and CD4 T lymphocytes into naïve T cells, TCM and TEM. Activation of CD4 and CD8 T cell subsets was determined by measuring upregulation of CD69, CD25 and HLA-DR. Serum levels of cytokines were determined as additional biomarkers for T cell activation. In 50% of patients at DL1 to DL3, CD4 and CD8 T cell counts increased during the course of treatment - over pre-treatment levels. The TEM subset from both CD4 and CD8 T cells accounted for most of the observed increases, while the naïve T cell subsets showed no increase but also no signs of apoptosis. The non-proliferative TEMRA subset of CD8 T cells also remained unchanged in most patients. This indicated that the selective increase of proliferation-competent TEM subsets was attributed to MT103-induced T cell proliferation. At DL4, all evaluable patients showed signs of T cell expansion after 2 weeks of MT103 infusion, which was most pronounced in those who developed a partial or complete remission. The increase of CD8 T cell counts was more pronounced than that of CD4 T cells. T cell expansion was accompanied by upregulation of T cell activation markers as well as by increases in serum concentrations of cytokines like IFN-γ. T cell expansion and activation reverted in all cases when the infusion of MT103 was stopped. In summary, MT103 induced a reversible secondary T cell response involving T cell activation and proliferation as well as T cell cytotoxicity against circulating B cells and lymphoma tissue. The dose-dependent T cell expansion observed during long-term infusion of MT103, particularly within the cytotoxic TEM subset of CD8 T cells, appears to play a key role for clinical activity.

Promoting Regulation Via the Inhibition of DNAM-1 After Transplantation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 338-338
Author(s):  
Motoko Koyama ◽  
Rachel D Kuns ◽  
Stuart D Olver ◽  
Katie E Lineburg ◽  
Mary Lor ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Steady State ◽  
T Cell ◽  
Median Survival ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Acute Gvhd ◽  
Cd4 T Cell

Abstract Abstract 338 Graft-versus-host disease (GVHD) is the major limitation of allogeneic hematopoietic bone marrow transplantation (BMT). Donor T cells play pivotal roles in GVHD and graft-versus-leukemia (GVL) effects and following BMT all T cell fractions, including regulatory T cells (Treg) express the DNAX accessory molecule-1 (DNAM-1, CD226) and T cell Immunoglobulin and ITIM domain (TIGIT) molecule. DNAM-1 is a co-stimulatory and adhesion molecule, expressed mainly by NK cells and CD8+ T cells at steady state to promote adhesion to ligand (CD155, CD112)–expressing targets and enhance cytolysis. TIGIT is a regulatory ligand expressed predominantly by Treg as steady state which competes for CD155 binding, We have analyzed the role of this pathway in GVHD and GVL. Lethally irradiated C3H/Hej (H-2k) mice were injected with bone marrow cells and T cells from MHC disparate wild-type (wt) or DNAM-1–/– C57Bl6 (H-2b) mice. Recipients of DNAM-1–/– grafts were protected from GVHD (survival 67% vs. 7%, P < .0001). We also confirmed the role of DNAM-1 in GVHD in a MHC-matched BMT model (B6 → BALB/B (H-2b)) where GVHD is directed to multiple minor histocompatibility antigens. Next we examined the donor populations expressing DNAM-1 which mediate this effect. DNAM-1 had little impact on acute GVHD severity in the B6 → bm1 BMT model where GVHD is directed against an isolated MHC class I mismatch and is CD8-dependent. In contrast, recipients of wt bone marrow and DNAM-1–/– CD4 T cells survived long-term (compared to recipients of wt CD4 T cells, survival 81% vs. 25%, P = .003) in the B6 → B6C3F1 BMT model, confirming the protection from GVHD is CD4-dependent. Donor CD4 T cell expansion and effector function (Th1 and Th17), and CD8 T cell expansion and cytotoxic function were equivalent in recipients of wt and DNAM-1–/– grafts. However the percentage and number of Treg were significantly increased in recipients of DNAM-1–/– grafts compared to those of wt grafts. The depletion of Treg from donor grafts eliminated the protection from GVHD seen in the absence of DNAM-1 signalling (median survival 16 days vs. 15.5 days, P = 0.53). Adoptive transfer experiments using FACS-sorted Treg were undertaken to compare the relative ability of B6.WT and B6.DNAM-1–/– Treg to suppress GVHD. The majority of recipients of DNAM-1–/– Treg survived beyond day 50 (median survival; day 56), demonstrating a superior ability to suppress acute GVHD relative to wt Treg where the median survival was day 36 (survival 47% vs. 0%, P = .001). These data demonstrate that donor DNAM-1 expression promotes GVHD in a CD4+ T cell-dependent manner via the inhibition of donor Foxp3+ Treg. Finally, the absence of donor DNAM-1 did not influence leukemia-specific mortality in multiple GVL models, regardless of whether the tumor expressed CD155 or not. Thus we demonstrate that the DNAM-1 pathway promotes GVHD, putatively due to competition with TIGIT on Treg, thereby inhibiting regulatory function. This provides support for therapeutic DNAM-1 inhibition to promote tolerance not only after transplant but also in relevant inflammatory based diseases characterized by T cell activation. Disclosures: No relevant conflicts of interest to declare.

Perforin Is Important For Both CD4+ and CD8+ T Cell-Mediated Graft-Versus-Tumor Effect But Plays Differential Roles In CD4+ and CD8+ T Cell Expansion After Allogeneic Transplantation

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3255-3255
Author(s):  
Nicholas Leigh ◽  
Guanglin Bian ◽  
Wei Du ◽  
George L. Chen ◽  
Hong Liu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cell Expansion ◽  
Cd8 T Cell ◽  
Cd4 T Cell ◽  
T Cell Proliferation ◽  
T Cell Expansion ◽  
Time Point

Abstract Graft versus tumor (GVT) effect is the desired and integral outcome for successful allogeneic bone marrow transplantation (allo-BMT) for cancer patients. This effect is dependent on T cell mediated recognition and elimination of residual host tumor cells present after allo-BMT. T cell killing is mediated primarily via three pathways: perforin/granzymes, Fas/FasL, and cytotoxic cytokines. Recent work from our lab has revealed a detrimental role for granzyme B (GzmB) in GVT effect due to its role in activation induced cell death (AICD) of CD8+ T cells. As a result, GzmB-/- CD8+ T cells exhibited higher expansion after allo-BMT and subsequently provided better tumor control. Our current study sought to determine the role of perforin (Prf1) in GVT effect mediated by both CD4+ and CD8+ T cells. Using the MHC-mismatched C57BL/6 (H-2b) to BALB/c (H-2d) allo-BMT model, we first confirmed previous findings that when transplanting CD8+ T cells along with T cell depleted (TCD) BM cells, donor CD8+ T cells require Prf1 to mediate GVT effect against allogeneic A20 lymphoma (Fig 1A, Prf1-/- (n=4) vs WT (n=4), *P<0.05). In addition, our data suggest that Prf1 is also required for CD4+ T cells to effectively mediate GVT effect against A20, as transplant with Prf1-/- CD4+CD25- T cells does not control tumor growth as well as WT controls (Fig 1B). Our previous work showed that GzmB deficiency allows for less AICD and subsequently more CD8+ T cell expansion. New data now show a similar effect for Prf1 in CD8+ T cell accumulation, as Prf1-/- CD8+ T cells outcompete WT CD8+ T cells (CD45.1+) when these two genotypes are mixed in equal numbers and transplanted into tumor bearing BALB/c mice (n=5/time point, *P=0.02 day 9)(Fig 1C). This competitive advantage was due to less AICD in the Prf1-/- CD8+ T cells. However, Prf1 appears to be required for efficient GVT activity, because the higher number of Prf1-/- CD8+ T cells are still less capable than WT counterparts in controlling tumor growth. We next tested the effect of Prf1 in AICD in CD4+CD25- T cells, and again co-transplanted WT CD45.1+ and Prf1-/- CD4+CD25- T cells into tumor bearing mice for a competition assay. Unexpectedly, WT CD4+CD25- T cells accumulate to significantly higher numbers when in direct competition with Prf1-/- CD4+CD25- T cells (n=4/time point, **,P<0.01)(Fig 1D). When we measured apoptotic cells with Annexin V staining, we found that WT CD4+CD25- T cells still had significantly more AICD (Prf1-/- 38.3 ± 4.2% vs. WT 48.1 ± 5.1%, P<0.01 on day 7 post-BMT; Prf1-/- 12.7 ± 1.0% vs. WT 18.1 ± 3.4%, P<0.03 on day 9 post-BMT). This result suggests that while Prf1 has an important role in AICD, it may also play a role in another feature of CD4+ T cell biology. We then explored the hypothesis that may Prf1 promote CD4+ T cell proliferation by evaluating Hoescht staining on day 9 post-BMT. Preliminary results suggest that Prf1 may enhance T cell proliferation, as Prf1-/- CD4+ T cells have less actively dividing cells at this time point. Therefore, Prf1 appears to have a surprising role after allo-BMT in sustaining T cell expansion for CD4+ T cells, but not for CD8+ T cells. Another factor influencing GVT effect may be T cell phenotype. Our previous work with CD8+ T cells suggests that more effector memory (CD62LLOWCD44HIGH) T cells accumulate in the absence of GzmB, and that GzmB-/- CD8+ T cells exhibited higher GVT activity than WT controls. We now found that while Prf1-/- CD4+ T cells also skewed towards the effector memory phenotype (CD62LLOWCD44HIGH), loss of Prf1 still reduced the ability of CD4+ T cells to control tumor growth in this model of allo-BMT. In summary, our results suggest that Prf1 plays an important role in GVT responses mediated not only by CD8+ T cells but also by CD4+ T cells, which were shown in previous literature to mainly utilize Fas ligand and cytokine systems to mediate GVT activity. In addition, Prf1 can cause AICD to both CD4+ and CD8+ T cells after allo-BMT. While Prf1-induced AICD reduces CD8+ T cell expansion, Prf1 appears to play a previously unrecognized role enhancing CD4+ T cell proliferation via an unidentified mechanism. Disclosures: No relevant conflicts of interest to declare.

Suppressive activity of regulatory T cells correlates with high CD4+ T-cell counts and low T-cell activation during chronic simian immunodeficiency virus infection

AIDS ◽  
2011 ◽  
Vol 25 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Ingrid Karlsson ◽  
Benoît Malleret ◽  
Patricia Brochard ◽  
Benoît Delache ◽  
Julien Calvo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Virus Infection ◽  
Regulatory T Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Cd4 T Cell ◽  
Suppressive Activity ◽  
Cell Counts ◽  
Immunodeficiency Virus

scholarly journals Severe and multifaceted systemic immunosuppression caused by experimental cancers of the central nervous system requires release of non-steroid soluble mediators

2020 ◽  
Author(s):  
K Ayasoufi ◽  
CK Pfaller ◽  
L Evgin ◽  
RH Khadka ◽  
ZP Tritz ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Unknown Etiology ◽  
Thymic Involution ◽  
Cell Counts ◽  
Hallmark Feature

AbstractImmunosuppression of unknown etiology is a hallmark feature of glioblastoma (GBM) and is characterized by decreased CD4 T cell counts and down regulation of MHC class II expression on peripheral blood monocytes in patients. This immunosuppression is a critical barrier to the successful development of immunotherapies for GBM. We recapitulated the immunosuppression observed in GBM patients in the C57BL/6 mouse and investigated the etiology of low CD4 T cell counts. We determined that thymic involution was a hallmark feature of immunosuppression in three distinct models of CNS cancer, including mice harboring GL261 glioma, B16 melanoma, and in a spontaneous model of Diffuse Intrinsic Pontine Glioma (DIPG). In addition to thymic involution, we determined that tumor growth in the brain induced significant splenic involution, reductions in peripheral T cells, reduced MHC class II expression on hematopoietic cells, and a modest increase in bone marrow resident CD4 T cells with a naïve phenotype. Using parabiosis we report that thymic involution, declines in peripheral T cell counts, and reduced MHC class II expression levels were mediated through circulating blood-derived factors. Conversely, T cell sequestration in the bone marrow was not governed through circulating factors. Serum isolated from glioma-bearing mice potently inhibited proliferation and functions of T cells both in vitro and in vivo. Interestingly, the factor responsible for immunosuppression in serum is nonsteroidal and of high molecular weight. Through further analysis of neurological disease models, we determined that the aforementioned immunosuppression was not unique to cancer itself, but rather occurs in response to CNS injury. Noncancerous acute neurological insults also induced significant thymic involution and rendered serum immunosuppressive. Both thymic involution and serum-derived immunosuppression were reversible upon clearance of brain insults. These findings demonstrate that CNS cancers cause multifaceted immunosuppression and pinpoint circulating factors as a target of intervention to restore immunity.Short SummaryCNS cancers and other brain-injuries suppress immunity through release of non-steroid soluble factors that disrupt immune homeostasis and dampen responses of the peripheral immune system.Graphical Abstract

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