scholarly journals Activating autoantibodies to the angiotensin II type I receptor play an important role in mediating hypertension in response to adoptive transfer of CD4+ T lymphocytes from placental ischemic rats

2012 ◽  
Vol 302 (10) ◽  
pp. R1197-R1201 ◽  
Author(s):  
Sarah Richards Novotny ◽  
Kedra Wallace ◽  
Judith Heath ◽  
Janae Moseley ◽  
Pushpinder Dhillon ◽  
...  
Keyword(s):  
Blood Pressure ◽  
T Cells ◽  
T Cell ◽  
Angiotensin Ii ◽  
T Lymphocytes ◽  
B Cell ◽  
Inflammatory Cytokines ◽  
Adoptive Transfer ◽  
Type I ◽  
Placental Ischemia

Hypertension in rats with chronic placental ischemia (reduced uterine perfusion pressure, RUPP) is associated with elevated inflammatory cytokines, agonistic autoantibodies to the angiotensin II type I receptor (AT1-AA) and CD4+ T cells; all of which are elevated in preclamptic women. Additionally, we have shown that adoptive transfer of RUPP CD4+ T cells increases blood pressure, inflammatory cytokines, and sFlt-1. The objective of this study was to determine the long-term effects of RUPP CD4+ T cells on AT1-AA, renal and systemic hemodynamics in pregnant rats. To answer this question CD4+ T splenocytes were magnetically isolated on day 19 of gestation from control RUPP and normal pregnant (NP) rats and injected into a new group of NP rats at day 13 of gestation. On day 19 of gestation mean arterial pressure (MAP) and renal function (glomerular filtration rates, GFR) were analyzed and serum collected for AT1-AA analysis. To determine a role for AT1-AA to mediate RUPP CD4+ T cell-induced blood pressure increases, MAP was analyzed in a second group of rats treated with AT1 receptor blockade losartan (10 mg·kg−1·day−1) and in a third group of rats treated with rituximab, a B cell-depleting agent (250 mg/kg) we have shown previously to decrease AT1-AA production in RUPP rats. MAP increased from 101 ± 2 mmHg NP to 126 ± 2 mmHg in RUPP rats ( P < 0.001) and to 123 ± 1 mmHg in NP rats injected with RUPP CD4+ T cells (NP+RUPP CD4+T cells) ( P < 0.001). Furthermore, GFR decreased from 2.2 ml/min ( n = 7) in NP rats to 1.0 ml/min ( n = 5) NP+RUPP CD4+T cell. Circulating AT1-AA increased from 0.22 ± 0.1 units in NP rats to 13 ± 0.7 ( P < 0.001) units in NP+RUPP CD4+T cell-treated rats but decreased to 8.34 ± 1 beats/min in NP+RUPP CD4+ T cells chronically treated with rituximab. Hypertension in NP+RUPP CD4+T cell group was attenuated by losartan (102 ± 4 mmHg) and with B cell depletion (101 ± 5 mmHg). Therefore, we conclude that one mechanism of hypertension in response to CD4+ T lymphocytes activated during placental ischemia is via AT1 receptor activation, potentially via AT1-AA during pregnancy.

scholarly journals Blockade of CD40 ligand for intercellular communication reduces hypertension, placental oxidative stress, and AT1-AA in response to adoptive transfer of CD4+ T lymphocytes from RUPP rats

2015 ◽  
Vol 309 (10) ◽  
pp. R1243-R1250 ◽  
Author(s):  
Denise C. Cornelius ◽  
Javier Castillo ◽  
Justin Porter ◽  
Lorena M. Amaral ◽  
Nathan Campbell ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Blood Pressure ◽  
T Cells ◽  
T Lymphocytes ◽  
Adoptive Transfer ◽  
Cell Communication ◽  
Cd40 Ligand ◽  
Type I ◽  
Uterine Perfusion ◽  
Placental Ischemia

Preeclampsia (PE) is associated with altered immune activation during pregnancy. We have previously shown that adoptive transfer of CD4+ T cells from the reduced uterine perfusion pressure (RUPP) rat model of PE increases blood pressure, oxidative stress (ROS), and inflammation in normal pregnant recipient rats. The objective of this study was to determine if blockade of communication via the CD40-CD40 ligand (CD40L) interaction between placental ischemia-induced CD4+ T cells with endogenous normal pregnant (NP) cells would improve pathophysiology that was previously observed in NP recipient rats of RUPP CD4+ T cells. Splenic CD4+ T lymphocytes were magnetically separated, incubated with 2.5 μg/ml anti-CD40 ligand (αCD40L) overnight, and transferred into NP rats on day 12 of gestation (NP+RUPP CD4+ T+anti-CD40L). On day 19 of gestation, blood pressure (MAP), blood, and tissues were collected. MAP was 99 ± 2 in NP ( n = 13), 116 ± 4 in NP+RUPP CD4+ T cells ( n = 7; P < 0.01); MAP only increased to 104 ± 2 in NP+RUPP CD4+ T cells+CD40L ( n = 24) ( P < 0.05 vs. NP+RUPP CD4+ T cells). Mechanisms of hypertension in response to RUPP CD4+ T cells include endothelin-1 (ET-1), ROS, and angiotensin II type I receptor (AT1-AA) were analyzed. Inhibition of CD40L binding reduced placental ET-1 to 2.3-fold above NP rats and normalized placental ROS from 318.6 ± 89 in NP+RUPP CD4+ T cells ( P < 0.05) to 118.7 ± 24 in NP+RUPP CD4+ T+anti-CD40L ( P < 0.05). AT1-AA was also normalized with inhibition of CD40L. These data suggest that placental ischemia-induced T-cell communication via the CD40L is one important mechanism leading to much of the pathophysiology of PE.

scholarly journals Role of the T cell in the genesis of angiotensin II–induced hypertension and vascular dysfunction

2007 ◽  
Vol 204 (10) ◽  
pp. 2449-2460 ◽  
Author(s):  
Tomasz J. Guzik ◽  
Nyssa E. Hoch ◽  
Kathryn A. Brown ◽  
Louise A. McCann ◽  
Ayaz Rahman ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Angiotensin Ii ◽  
Nadph Oxidase ◽  
Adoptive Transfer ◽  
Vascular Function ◽  
Type I ◽  
Perivascular Adipose Tissue

Hypertension promotes atherosclerosis and is a major source of morbidity and mortality. We show that mice lacking T and B cells (RAG-1−/− mice) have blunted hypertension and do not develop abnormalities of vascular function during angiotensin II infusion or desoxycorticosterone acetate (DOCA)–salt. Adoptive transfer of T, but not B, cells restored these abnormalities. Angiotensin II is known to stimulate reactive oxygen species production via the nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase in several cells, including some immune cells. Accordingly, adoptive transfer of T cells lacking the angiotensin type I receptor or a functional NADPH oxidase resulted in blunted angiotensin II–dependent hypertension and decreased aortic superoxide production. Angiotensin II increased T cell markers of activation and tissue homing in wild-type, but not NADPH oxidase–deficient, mice. Angiotensin II markedly increased T cells in the perivascular adipose tissue (periadventitial fat) and, to a lesser extent the adventitia. These cells expressed high levels of CC chemokine receptor 5 and were commonly double negative (CD3+CD4−CD8−). This infiltration was associated with an increase in intercellular adhesion molecule-1 and RANTES in the aorta. Hypertension also increased T lymphocyte production of tumor necrosis factor (TNF) α, and treatment with the TNFα antagonist etanercept prevented the hypertension and increase in vascular superoxide caused by angiotensin II. These studies identify a previously undefined role for T cells in the genesis of hypertension and support a role of inflammation in the basis of this prevalent disease. T cells might represent a novel therapeutic target for the treatment of high blood pressure.

scholarly journals B cell depletion impairs vaccination-induced CD8+ T cell responses in a type I interferon-dependent manner

2021 ◽  
pp. annrheumdis-2021-220435
Author(s):  
Theresa Graalmann ◽  
Katharina Borst ◽  
Himanshu Manchanda ◽  
Lea Vaas ◽  
Matthias Bruhn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cell Expansion ◽  
De Novo ◽  
T Cell Responses ◽  
Type I ◽  
Cell Responses ◽  
T Cell Expansion

ObjectivesThe monoclonal anti-CD20 antibody rituximab is frequently applied in the treatment of lymphoma as well as autoimmune diseases and confers efficient depletion of recirculating B cells. Correspondingly, B cell-depleted patients barely mount de novo antibody responses during infections or vaccinations. Therefore, efficient immune responses of B cell-depleted patients largely depend on protective T cell responses.MethodsCD8+ T cell expansion was studied in rituximab-treated rheumatoid arthritis (RA) patients and B cell-deficient mice on vaccination/infection with different vaccines/pathogens.ResultsRituximab-treated RA patients vaccinated with Influvac showed reduced expansion of influenza-specific CD8+ T cells when compared with healthy controls. Moreover, B cell-deficient JHT mice infected with mouse-adapted Influenza or modified vaccinia virus Ankara showed less vigorous expansion of virus-specific CD8+ T cells than wild type mice. Of note, JHT mice do not have an intrinsic impairment of CD8+ T cell expansion, since infection with vaccinia virus induced similar T cell expansion in JHT and wild type mice. Direct type I interferon receptor signalling of B cells was necessary to induce several chemokines in B cells and to support T cell help by enhancing the expression of MHC-I.ConclusionsDepending on the stimulus, B cells can modulate CD8+ T cell responses. Thus, B cell depletion causes a deficiency of de novo antibody responses and affects the efficacy of cellular response including cytotoxic T cells. The choice of the appropriate vaccine to vaccinate B cell-depleted patients has to be re-evaluated in order to efficiently induce protective CD8+ T cell responses.

scholarly journals Epiligrin, a component of epithelial basement membranes, is an adhesive ligand for alpha 3 beta 1 positive T lymphocytes.

1993 ◽  
Vol 121 (5) ◽  
pp. 1141-1152 ◽  
Author(s):  
E A Wayner ◽  
S G Gil ◽  
G F Murphy ◽  
M S Wilke ◽  
W G Carter
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
Basement Membrane ◽  
B Cell ◽  
Cell Lines ◽  
B Cell Lymphoma ◽  
Lymphokine Activated Killer Cells ◽  
Cutaneous Inflammation ◽  
Epidermal Basement Membrane

The cutaneous T cell lymphomas (CTCL), typified by mycosis fungoides, and several chronic T cell mediated dermatoses are characterized by the migration of T lymphocytes into the epidermis (epidermotropism). Alternatively, other types of cutaneous inflammation (malignant cutaneous B cell lymphoma, CBCL, or lymphocytoma cutis, non-malignant T or B cell type) do not show evidence of epidermotropism. This suggests that certain T lymphocyte subpopulations are able to interact with and penetrate the epidermal basement membrane. We show here that T lymphocytes derived from patients with CTCL (HUT 78 or HUT 102 cells), adhere to the detergent-insoluble extracellular matrix prepared from cultured basal keratinocytes (HFK ECM). HUT cell adhesion to HFK ECM was inhibitable with monoclonal antibodies (mAbs) directed to the alpha 3 (P1B5) or beta 1 (P4C10) integrin receptors, and could be up-regulated by an activating anti-beta 1 mAb (P4G11). An inhibitory mAb, P3H9-2, raised against keratinocytes identified epiligrin as the ligand for alpha 3 beta 1 positive T cells in HFK ECM. Interestingly, two lymphocyte populations could be clearly distinguished relative to expression of alpha 3 beta 1 by flow cytometry analysis. Lymphokine activated killer cells, alloreactive cytotoxic T cells and T cells derived from patients with CTCL expressed high levels of alpha 3 beta 1 (alpha 3 beta 1high). Non-adherent peripheral blood mononuclear cells, acute T or B lymphocytic leukemias, or non-cutaneous T or B lymphocyte cell lines expressed low levels of alpha 3 beta 1 (alpha 3 beta 1low). Resting PBL or alpha 3 beta 1low T or B cell lines did not adhere to HFK ECM or purified epiligrin. However, adhesion to epiligrin could be up-regulated by mAbs which activate the beta 1 subunit indicating that alpha 3 beta 1 activity is a function of expression and affinity. In skin derived from patients with graft-vs.-host (GVH) disease, experimentally induced delayed hypersensitivity reactions, and CTCL, the infiltrating T cells could be stained with mAbs to alpha 3 or beta 1 and were localized in close proximity to the epiligrin-containing basement membrane. Infiltrating lymphocytes in malignant cutaneous B disease (CBCL) did not express alpha 3 beta 1 by immunohistochemical techniques and did not associate with the epidermal basement membrane. The present findings clearly define a function for alpha 3 beta 1 in T cells and strongly suggest that alpha 3 beta 1 interaction with epiligrin may be involved in the pathogenesis of cutaneous inflammation.

Vaccine-elicited CD4 T cells prevent the deletion of antiviral B cells in chronic infection

2021 ◽  
Vol 118 (46) ◽  
pp. e2108157118
Author(s):  
Kerstin Narr ◽  
Yusuf I. Ertuna ◽  
Benedict Fallet ◽  
Karen Cornille ◽  
Mirela Dimitrova ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Memory B Cells ◽  
Type I ◽  
Clonal Deletion ◽  
Cell Immunity ◽  
B Cell Immunity

Chronic viral infections subvert protective B cell immunity. An early type I interferon (IFN-I)–driven bias to short-lived plasmablast differentiation leads to clonal deletion, so-called “decimation,” of antiviral memory B cells. Therefore, prophylactic countermeasures against decimation remain an unmet need. We show that vaccination-induced CD4 T cells prevented the decimation of naïve and memory B cells in chronically lymphocytic choriomeningitis virus (LCMV)-infected mice. Although these B cell responses were largely T independent when IFN-I was blocked, preexisting T help assured their sustainability under conditions of IFN-I–driven inflammation by instructing a germinal center B cell transcriptional program. Prevention of decimation depended on T cell–intrinsic Bcl6 and Tfh progeny formation. Antigen presentation by B cells, interactions with antigen-specific T helper cells, and costimulation by CD40 and ICOS were also required. Importantly, B cell–mediated virus control averted Th1-driven immunopathology in LCMV-challenged animals with preexisting CD4 T cell immunity. Our findings show that vaccination-induced Tfh cells represent a cornerstone of effective B cell immunity to chronic virus challenge, pointing the way toward more effective B cell–based vaccination against persistent viral diseases.

scholarly journals Safety Profile of a Virus-Like Particle-Based Vaccine Targeting Self-Protein Interleukin-5 in Horses

Vaccines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 213 ◽  
Author(s):  
Sigridur Jonsdottir ◽  
Victoria Fettelschoss ◽  
Florian Olomski ◽  
Stephanie C. Talker ◽  
Jelena Mirkovitch ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Mononuclear Cells ◽  
Clinical Signs ◽  
T Cell Response ◽  
Type I ◽  
Cell Responses ◽  
Virus Like Particle ◽  
Ifn Γ

Background: Insect bite hypersensitivity (IBH) is an eosinophilic allergic dermatitis of horses caused by type I/IVb reactions against mainly Culicoides bites. The vaccination of IBH-affected horses with equine IL-5 coupled to the Cucumber mosaic virus-like particle (eIL-5-CuMVTT) induces IL-5-specific auto-antibodies, resulting in a significant reduction in eosinophil levels in blood and clinical signs. Objective: the preclinical and clinical safety of the eIL-5-CuMVTT vaccine. Methods: The B cell responses were assessed by longitudinal measurement of IL-5- and CuMVTT-specific IgG in the serum and plasma of vaccinated and unvaccinated horses. Further, peripheral blood mononuclear cells (PBMCs) from the same horses were re-stimulated in vitro for the proliferation and IFN-γ production of specific T cells. In addition, we evaluated longitudinal kidney and liver parameters and the general blood status. An endogenous protein challenge was performed in murine IL-5-vaccinated mice. Results: The vaccine was well tolerated as assessed by serum and cellular biomarkers and also induced reversible and neutralizing antibody titers in horses and mice. Endogenous IL-5 stimulation was unable to re-induce anti-IL-5 production. The CD4+ T cells of vaccinated horses produced significantly more IFN-γ and showed a stronger proliferation following stimulation with CuMVTT as compared to the unvaccinated controls. Re-stimulation using E. coli-derived proteins induced low levels of IFNγ+CD4+ cells in vaccinated horses; however, no IFN-γ and proliferation were induced following the HEK-eIL-5 re-stimulation. Conclusions: Vaccination using eIL-5-CuMVTT induces a strong B-cell as well as CuMVTT-specific T cell response without the induction of IL-5-specific T cell responses. Hence, B-cell unresponsiveness against self-IL-5 can be bypassed by inducing CuMVTT carrier-specific T cells, making the vaccine a safe therapeutic option for IBH-affected horses.

CLL Cells Can Diversify, Switch, and Differentiate in Response to Autologous T Cell Stimuli Present in a Murine Adoptive Transfer Model

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 315-315
Author(s):  
Piers E.M. Patten ◽  
Shih-Shih Chen ◽  
Davide Bagnara ◽  
Rita Simone ◽  
Sonia Marsilio ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Adoptive Transfer ◽  
De Novo ◽  
Conflicts Of Interest ◽  
Transfer Model ◽  
B Cell Differentiation ◽  
Cell Numbers ◽  
Nsg Mice

Abstract Abstract 315 Adoptive transfer of primary patient CLL cells into NOD/SCID/γcnull(NSG) mice results in engraftment and proliferation of CLL cells if autologous T cells are present. Formation of splenic follicles consisting of B cells interspersed and surrounded by T cells indicates engraftment. However, ultimately these CD20+ cells are lost several weeks later. We describe one of the mechanisms for this apparent loss: differentiation to plasma cells. Peripheral blood cells from 9 IgM+ CLL patients (6 U-CLL and 3 M-CLL) were adoptively transferred into NSG mice with enriched autologous CD3+ cells pre-activated with anti-CD3/28 beads. B and T cell engraftment and subset distributions were analyzed for 47 mice by immunohistochemistry (IHC) and flow cytometry (FC) at the time of sacrifice. The earliest and latest times of assessment were 12 and 124 days, respectively, after CLL cell injection. In some cases, CLL cells were labeled with CFSE to track cell division. At sacrifice, 3 engraftment patterns were observed. Pattern 1 (observed up to day 56) showed small follicles of CD20+ cells with low-moderate numbers of surrounding T cells. Intensely positive CD38 cells were inconspicuous. FC showed CD19+CD5+ cells with no increase in CD38 and variable CFSE dilution indicating lower levels of proliferation. Pattern 2 (observed throughout the study period) showed much higher T and B cell numbers. CD20+ cells were interspersed with and surrounded by principally CD4+ cells which were activated and functional as indicated by expression of Ki-67, PD-1, CD57, and T cell derived cytokines IFNγ and IL5 in plasma. Follicles contained CD20 and cytoplasmic Ig+ (cIg+) cells that double stained for IRF-4 and Blimp-1, transcription factors required for B cell differentiation. While Bcl-6 staining in these cells was minimal or absent, follicles from all 9 patients contained activation-induced deaminase (AID)+ cells. Cells with dim IgM expression localized to follicles; however, cells with intense IgM, IgA, or IgG were present both within, surrounding, and outside follicles matched by similar CD38 staining. Smaller populations of CD138+ cells surrounded follicles and were interspersed throughout non-follicular splenic areas. FC showed a novel CD19+CD5-CFSE-CD38++ population containing a CD138+ subset. Pattern 3 (observed in a limited subset of cases not before day 63) had minimal CD20+ cells by IHC, but noticeable populations of cIg+CD38+ and CD138+ cells interspersed amongst plentiful T cells. Such cells corresponded with cells with plasma cell morphology. Confirmation that differentiated cells were from the patient clone was achieved in 3 ways. First, in FACS sorted CD19+CD5+ and CD19+CD5-38++ cells from a subset of pattern 2 cases, RT-PCR revealed that all fractions contained both IGHC unswitched and switched clones identical to those found in the patients. Second, cases with pattern 3 engraftment generated CLL clonal switched and unswitched cDNA sequences. Finally, adoptive transfer of highly purified CD5+CD19+ patient cells generated IRF-4+Blimp-1+CD138+ cells. The generation of switched cells from all 9 patients indicated functional AID. In one U- CLL case, ultra-deep sequencing on pre-transfer and post-transfer human cells taken from mouse spleen revealed a significant number of new IGHVDJ mutations in spleen-derived cells. Such mutations targeted nucleotides typical for AID's action. In conclusion, CLL cells can diversify, switch, and differentiate in NSG mice in response to autologous T cell signals. The extent of this maturation is a function of T cell numbers and activity and the duration of the experiment. Differentiation without significant Bcl-6 expression suggests that follicles in NSG mice are not recapitulating classic germinal center reactions, possibly giving clues to the origin of CLL. Several features of poor prognosis disease were demonstrated (e.g., increased CD38 and AID expression with the development of clonally related switched transcripts) that might mirror clinical disease features. AID expressed by CLL cells is fully functional as indicated by de novo somatic hypermutation and class switch recombination. Both U-CLL and M-CLL clones respond in a similar manner in this model, suggesting the importance of T– B cell interactions in all types of CLL. Finally, the demonstration that cells can differentiate when appropriately induced may lead to novel therapeutic options for CLL. Disclosures: No relevant conflicts of interest to declare.

GMP-Grade Generation of B-Lymphocytes for Adoptive Immunotherapy in Patients After Allogeneic Stem Cell Transplantation

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4352-4352
Author(s):  
Julia Winkler ◽  
Michael Mach ◽  
Juergen Zingsem ◽  
Volker Weisbach ◽  
Andreas Mackensen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
B Cell ◽  
B Lymphocytes ◽  
Clinical Setting ◽  
One Step ◽  
Enrichment Protocol ◽  
The One

Abstract Abstract 4352 Background and objectives: We have recently shown that memory B-lymphocytes from murine CMV immune donor animals adoptively transferred into immunodeficient mice were highly effective in protecting from a viral infection indicating a therapeutic potential of virus specific memory B-cells. These preclinical data provided evidence that a cell-based strategy supporting the humoral immune response might be effective in a clinical setting of post-HSCT immunodeficiency (Klenovsek et al., 2007, Blood 110: 3472–9). As adoptive transfer of B-cells has not been used before in a clinical setting, it is necessary to establish a technology for the generation of GMP-grade B-cell products. Methods: Starting from the leukapheresis of healthy donors, B-cells were purified by two different separation strategies using GMP-grade microbeads and the CliniMACS∧TM device. A one-step protocol was used for positive enrichment of B-lymphocytes with anti-CD19 microbeads. In a two-step enrichment protocol, first T-lymphocytes were depleted by anti-CD3 microbeads and the remaining fraction was positively selected by anti-CD19 microbeads. Results: The leukapheresis contained a mean of 9.0×10∧8 CD19-positive B-cells (4.5–12.4 ×10∧8). After the one-step positive purification strategy a mean purity of CD20∧+ B-lymphocytes of 78.1% with a recovery of 32–41% was obtained. With the two-step T-cell depletion/B-cell enrichment protocol we achieved a mean purity of 96.4 % (93.4–97.8%) with a slightly lower recovery of 14–37%. The absolute B-cell numbers obtained in the product were 1.3 to 4.0 ×10∧8 and 1.7 to 2.6 ×10∧8 for the one-step positive enrichment and the two-step protocol, respectively. Importantly, the absolute number of T-cells was lower in cell products after the two-step protocol (0.1 to 0.9 ×10∧6 T-cells) as compared to the one-step positive CD19-enrichment (1.6 to 3.4 ×10∧6 T-cells). Assuming a patient with 70 kg body weight, the B-cell products obtained after the combined CD3-depletion and CD19-enrichment contained less then 4×10∧4 T-lymphocytes/kg bodyweight, which is a critical threshold number of T-cells in haploidentical HSCT. The B-cell products showed antibody production after in vitro stimulation in a limiting dilution assay and showed excellent viability after cryopreservation. Conclusions: A GMP-grade B-cell product can be obtained with high purity and very low T-cell contamination using the two-step enrichment protocol based on CliniMACS∧TM technology. (Supported by BayImmuNet) Disclosures: No relevant conflicts of interest to declare.

Lenalidomide Promotes The Expansion Of CD8 T Cells With An Effector Memory Phenotype In a Murine Xenograft Model Of Chronic Lymphocytic Leukemia

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 119-119
Author(s):  
Rita Simone ◽  
Sonia Marsilio ◽  
Piers E.M. Patten ◽  
Gerardo Ferrer ◽  
Shih-Shih Chen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
T Lymphocytes ◽  
B Cell ◽  
Xenograft Model ◽  
Lymphocytic Leukemia ◽  
Effector Memory ◽  
Cell Engraftment

Abstract Lenalidomide (Revlimid®), a thalidomide analogue, is an orally administered second generation immunomodulator with anti-angiogenic and anti-neoplastic properties. Initial studies treating patients with chronic lymphocytic leukemia (CLL) suggest that lenalidomide can have considerable efficacy and that its mode of action is mainly indirect, affecting non-malignant cells in the microenvironment, in particular T lymphocytes. Because a recently described xenograft model for CLL has highlighted the importance of CLL-derived, autologous T cells in promoting leukemic B-cell engraftment and growth in vivo, we have studied the influence of lenalidomide on the expansion of CLL B- and T-lymphocytes in this model. After an initial 12 day culture of FACS-isolated CLL-derived T cells with or without anti-CD3/CD28 beads plus IL-2 (30 IU/ml), T lymphocytes were transferred into alymphoid NSG mice via the retro-orbital plexus (day 0). On day 7, CLL cells were delivered retro-orbitally. These recipient animals are referred to as “T + PBMC mice”. Mice that did not receive T cells on day 0 but were given CLL PBMCs at day 7, with or without lenalidomide, served as controls (“PBMC only mice”). Recipient mice received lenalidomide (10mg/kg/day) or vehicle control daily by gavage starting at day 0. All mice were sacrificed at day 28 (28 days after T-cell and 21 days after B-cell transfer), and blood, spleen, and bone marrow were collected. On this material, four analyses were performed: [1] level of human CD45+ cell engraftment; [2] numbers and types of CLL-derived T cells; [3] numbers of CLL B cells; and [4] levels of cytokines reflective of Th1 and Th2 immune responses. There was a clear enhancement in human hematopoietic (CD45+) cell engraftment in those mice exposed to lenalidomide. This was most marked for the PBMC only mice (vehicle: 10.64%; lenalidomide: 38.53%), although it was also evident for T + PBMC mice (vehicle: 55.96%; lenalidomide: 69.65%). T-cell phenotyping was carried out, before and after cell culture and also at sacrifice. Prior to culture, CLL samples contained on average ∼96% CD5+CD19+ cells and ∼3% CD5+CD19- cells; for the latter, ∼67% were CD4+ and ∼33% CD8+. After 12-day culture, these percentages remained largely unchanged. However, the numbers and types of T cells recovered from the spleens at sacrifice were quite different after in vivo exposure to lenalidomide. For the PBMC only, the percentages of CD4+ and CD8+ cells in the spleens differed somewhat based on lenalidomide exposure (CD4: Vehicle 86% vs. Lenalidomide 61%; CD8: Vehicle 10% vs. Lenalidomide 28%). However, this change was dramatic for the T + PBMC mice (CD4: Vehicle 64.1% vs. Lenalidomide 28.9%; CD8: Vehicle 34% vs. Lenalidomide 62%). Furthermore, when the CD8+ cells from these animals were subsetted based on antigen-experience and function, it appeared that lenalidomide exposure had led to the outgrowth of a greater number of effector memory (CD45RO+ CD62L-) than central memory (CD45RO+ CD62L+) T-cells. For CLL-derived B cells, the numbers differed, based not only on lenalidomide exposure but also on prior in vitro activation. Specifically, in PBMC only mice, the addition of lenalidomide led to increased numbers of CLL B cells in the spleen (Vehicle: 7.81% vs. Lenalidomide: 14%). Conversely, in the T + PBMC mice, the numbers of B cells decreased (Vehicle: 2.36% vs. Lenalidomide: 0.34%). An analysis of Th1 and Th2-related cytokines in the plasmas of the mice at sacrifice revealed a fall in IL-4, IL-5, and IL-10 and a marked increase in IFNg, consistent with a Th2 to Th1 transition. The above data suggest that administration of lenalidomide permits greater engraftment of human hematopoietic cells in alymphoid mice. Although this enhancement involves all members of the hematopoietic lineage, T cells, in particular CD8+ effector memory T cells, emerge in excess over time. This CD8 expansion is associated with diminished levels of CLL B cells suggesting that the decrease is due to T-cell mediated cytolysis. In contrast, in the absence of prior T-cell activation, CLL T cells appear to support better CLL B-cell growth. These findings suggest that lenalidomide alters B-cell expansion in vivo depending on the activation and differentiation state of the autologous T-cell compartment. They also implicate the generation of cytolytic T cells as one mechanism whereby lenalidomide leads to clinical improvement in CLL. Disclosures: Allen: Celgene Corporation: Honoraria.

scholarly journals Streptococcal Pyrogenic Exotoxin A-Stimulated Monocytes Mediate Regulatory T-Cell Accumulation through PD-L1 and Kynurenine

2019 ◽  
Vol 20 (16) ◽  
pp. 3933 ◽  
Author(s):  
Katharina Giesbrecht ◽  
Sandra Förmer ◽  
Aline Sähr ◽  
Klaus Heeg ◽  
Dagmar Hildebrand
Keyword(s):  
T Cells ◽  
Cell Death ◽  
T Cell ◽  
T Lymphocytes ◽  
Mhc Class Ii ◽  
Inflammatory Cytokines ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Exotoxin A ◽  
T Effector Cells

Bacterial superantigens (SAgs) are exotoxins that promote a fulminant activation of the immune system. The subsequent intense release of inflammatory cytokines often results in hypotension, shock, and organ failure with high mortality rates. In the current paradigm, the direct and simultaneous binding of SAgs with T-cell receptor (TCR)-bearing Vβ regions and conserved structures on major histocompatibility complex class II (MHC class II) on antigen-presenting cells (APCs) induces the activation of both cell types. However, by crosslinking MHC class II molecules, APCs can be activated by SAgs independently of T lymphocytes. Recently, we showed that streptococcal pyrogenic exotoxin A (SPEA) of Streptococcus pyogenes stimulates an immunogenic APC phenotype with upregulated costimulatory molecules and inflammatory cytokines. Additionally, we revealed that SPEA triggers immunosuppressive programs in monocytes that facilitate the accumulation of regulatory T cells (Tregs) in in vitro monocyte/CD4+ T-cell cocultures. Immunosuppressive factors include anti-inflammatory interleukin 10 (IL-10), co-inhibitory surface molecule programmed cell death 1 ligand 1 (PD-L1), and the inhibitory indoleamine 2,3-dioxygenase (IDO)/kynurenine effector system. In the present study, we investigated the underlying mechanism of SPEA-stimulated monocyte-mediated accumulation of Tregs. Blood-derived monocytes from healthy donors were stimulated with SPEA for 48 h (SPEA-monocytes). For the evaluation of SPEA-monocyte-mediated modulation of CD4+ T lymphocytes, SPEA was removed from the culture through extensive washing of cells before adding allogeneic CD3/CD28-activated T cells. Results: In coculture with allogeneic CD4+ T cells, SPEA-monocytes mediate apoptosis of CD4+Foxp3− lymphocytes and accumulation of CD4+Foxp3+ Tregs. PD-L1 and kynurenine are critically involved in the mediated cell death because blocking both factors diminished apoptosis and decreased the proportion of the CD25+/Foxp3+ Treg subpopulation significantly. Upregulation of PD-L1 and kynurenine as well as SPEA-monocyte-mediated effects on T cells depend on inflammatory IL-1β. Our study shows that monocytes activated by SPEA mediate apoptosis of CD4+Foxp3− T effector cells through PD-L1 and kynurenine. CD4+Foxp3+ T cells are resistant to apoptosis and accumulate in SPEA-monocyte/CD4+ T-cell coculture.

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