Faculty Opinions recommendation of Tolerance induction of alloreactive T cells via ex vivo blockade of the CD40:CD40L costimulatory pathway results in the generation of a potent immune regulatory cell.

We previously reported that ex vivo blockade of the CD40:CD40L costimulatory pathway in primary mixed lymphocyte reaction cultures resulted in profound in vitro secondary hyporesponsiveness and 30-fold or greater protection from graft-versus-host-disease (GVHD) lethality. Present studies demonstrate that tolerance induction via costimulatory blockade also results in the generation of a potent immunoregulatory cell that inhibits both naive and primed alloresponses. The immunoregulatory capacity was dependent upon cell-to-cell contact that prevented the full activation of the naive or primed cells. The inhibitory effect of tolerized cells did not preclude the response of naive T cells to nominal protein antigen if antigen was present at high concentration. However, under suboptimal antigen concentration, nonspecific inhibition of responses occurred. The tolerized regulatory cell population maintained a polyclonal T-cell receptor Vβ repertoire that was broader than in control primed cultures. These data, the first to demonstrate that tolerance induction via CD40:CD40L costimulatory blockade results in potent regulatory function, are relevant to bone-marrow and solid-organ transplantation. The generation of potent immunoregulatory capacity during tolerization via CD40:CD40L blockade provides a fail-safe mechanism to control alloreactive T cells that may have escaped tolerization. These potent regulatory cells may be clinically exploitable for the treatment and prevention of GVHD or autoimmunity.

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Ex Vivo Blockade of NF-[dappa]B Signaling in Alloreactive T Cells Prevents Murine Graft-Versus-Host Disease (GVHD).

Blood ◽

10.1182/blood.v104.11.3058.3058 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3058-3058

Author(s):

Matthew J. O’Shaughnessy ◽

Christine Vogtenhuber ◽

Jonathon S. Serody ◽

Raquel Sitcheran ◽

Albert S. Baldwin ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Mhc Class Ii ◽

Cd4 T Cells ◽

Ex Vivo ◽

Tolerance Induction ◽

Class Ii ◽

Maximal Effect ◽

Alloreactive T Cells ◽

Iκb Kinase

Abstract A failure of IL-2 transcription has been associated with tolerance induction. We hypothesized that inhibition of the NF-κB pathway in alloreactive T-cells, which is critical for IL-2 transcription, could lead to alloantigen-specific hyporesponsiveness and prevention of GVHD. PS1145, a potent inhibitor of IκB kinase, and hence NF-κB activation, was added to an MLR culture consisting of CD4+ T-cells and MHC class II-disparate stimulators. Inhibition of NF-κB activity was verified by EMSA and confocal microscopy. Global inhibition of cytokine production and T-cell hyporesponsiveness was observed which persisted after washing T-cells and re-exposure to alloantigen. Responses to non-specific mitogens remained largely intact and alloantigen hyporesponsiveness was reversed by exogenous IL-2. Treatment of T cells and stimulator cells with PS1145 was required for maximal effect. Depletion of CD4+CD25+ cells from the MLR indicated that these cells were not required for tolerance induction in this system. Using an MLR system containing alloreactive and non-alloreactive transgenic T cells indicated that PS1145 treatment increased the rate of T-cell apoptosis selectively in alloreactive cells. Data from each of 4 experiments showed that GVHD in recipients of ex vivo PS1145 treated cells was profoundly inhibited, whereas CD4+ T-cells recovered from a vehicle-treated 7-day MLR were uniformly fatal upon adoptive transfer into sublethally irradiated MHC class II-disparate recipients. Studies addressing non-alloreactive in vivo responses of PS1145 treated T cells will also be presented. Our studies indicate that the NF-κB pathway is a critical regulator of productive alloresponses and provide a novel ex vivo approach to induce alloantigen-specific tolerance as a means of preventing GVHD.

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Depletion of alloreactive T cells for tolerance induction in a recipient of kidney and hematopoietic stem cell transplantations

Pediatric Transplantation ◽

10.1111/j.1399-3046.2012.01701.x ◽

2012 ◽

Vol 16 (8) ◽

pp. E342-E347

Author(s):

Kanchana Tangnararatchakit ◽

Wiwat Tirapanich ◽

Usanarat Anurathapan ◽

Wiwat Tapaneya-Olarn ◽

Samart Pakakasama ◽

...

Keyword(s):

T Cells ◽

Stem Cell ◽

Hematopoietic Stem Cell ◽

Tolerance Induction ◽

Hematopoietic Stem ◽

Alloreactive T Cells

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Improvement of Selective Depletion of Alloreactive T Cells.

Blood ◽

10.1182/blood.v106.11.1067.1067 ◽

2005 ◽

Vol 106 (11) ◽

pp. 1067-1067

Author(s):

Erkut Bahceci ◽

Marina Komarovskaya ◽

Robert Kreitman ◽

Dennis Cooper ◽

Ira Pastan

Keyword(s):

T Cells ◽

Culture Media ◽

Ex Vivo ◽

Residual Activity ◽

Third Party ◽

Thymidine Uptake ◽

Activated T Cells ◽

Hematopoietic Stem ◽

Alloreactive T Cells ◽

Selective Depletion

Abstract Severe T cell depletion required for allogeneic hematopoietic stem cell transplantation from haplo-identical donors results in poor immune reconstitution and leads to high rates of mortality from infections, and relapse. One approach to overcome this problem is to infuse T cells depleted of alloreactivity. Selective depletion (SD) of alloreactive T cells is achieved by elimination of activated T cells after ex-vivo stimulation with recipient cells. To determine optimum selective depletion conditions, we have investigated the factors that modify alloreactivity of T cells. Methods: Alloreactivity was measured by one-way mixed lymphocyte reaction (MLR) using 3H thymidine uptake. PBMCs were used as responders and either irradiated expanded T cells (expT) or dendritic cells (DCs) as stimulators. T cells were expanded using anti-CD3 coated beads. DCs were generated from monocytes by GM-CSF and IL-4 stimulation. Selective depletion was performed by co-incubation of responder and stimulator cells for 72 hours and depletion of activated cells by an immunotoxin, LMB-2 (Anti-Tac (Fv)-PE-38), which was added to the culture at 24 and 48 hours. Effectiveness of the depletion was tested by a secondary MLR utilizing the original stimulator cells and unrelated third part cells. Results: Expansion of T cells has resulted in increase of HLA-DR, CD80 and CD86 expression compared to resting T cells (52.5% vs. 6%, 20.9% vs. 0.9%, and 32.9% vs. 20.9%, respectively), resulting in better stimulation in MLR (6505 cpm vs 1620 cpm). In one-way MLR using either PBMCs or CD25 depleted PBMCs as responders and expanded T cells and DCs as targets, with or without anti-CD28 in the culture media. DCs were better stimulators than expT cells (6636 vs. 4308). However, most dramatic effect was seen when anti-CD28 was added to the culture, increasing response to both expT cells and to a lesser extent DCs (40,169 and 19,303). Removal of CD25 positive cells also improved alloreactivity in all culture conditions (6636 in expT, 16,644 in DC, 57,363 in expT+CD28, and 30,943 in DC+CD28). To better define the effect of the target, we have performed Vbeta repertoire analysis of responding cells after expT cell, DC and expT cell+anti-CD28 stimulation. Flow cytometry revealed expansion of discrete Vbeta families, in addition to shared ones. We have then performed selective depletion using PBMCs or CD 25 depleted PBMCs as stimulators and expT cells, expT cell+anti-CD28, and DCs as stimulators. Residual alloreactivity after expT cell stimulation against original stimulators, DCs and third party cells were 7%, 147% and 99% respectively. Interestingly, after SD utilizing DCs as stimulators, there was substantial residual activity against expT cells (69%). When SD was performed using expT cells as stimulators with anti-CD28, combined with CD25 depletion, the depletion against both original stimulators and DCs was improved (2% and 54%, respectively). Conclusion: Depletion of regulatory T cells, and co-stimulation with ant-CD28 improves alloreactivity and selective depletion. Whether improvement in in-vitro selective depletion will result in better clinical outcome will be tested in a clinical trial.

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Depletion of Alloreactive T Cells after Haploidentical HSCT: Comparison of Outcomes for Ex Vivo Versus In Vivo Treatment Strategies

Blood ◽

10.1182/blood-2018-99-118857 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3474-3474

Author(s):

Steven Devine ◽

Stephan Mielke ◽

Eduardo Olavarria ◽

Bert Tuk ◽

Kees Meewisse ◽

...

Keyword(s):

Clinical Trials ◽

T Cells ◽

Single Dose ◽

T Cell ◽

Ex Vivo ◽

Chronic Gvhd ◽

Weighted Average ◽

Alloreactive T Cells ◽

Relapse Rates

Abstract Background: The use of haploidentical allogeneic hematopoietic stem cell transplantation (haplo-HSCT) has increased owing to therapeutic advances that have mitigated the main barriers such as high incidence of graft-versus-host disease (GVHD) and non-relapse mortality (NRM). This is primarily attributable to the elimination of alloreactive T cells in either the patient or the graft. Such T-cell depletion can be performed in vivo early after T-cell-replete haplo-HSCT using post-transplant cyclophosphamide (PTCy). Alternatively, T-cell-depleted haplo-HSCT can be supplemented with T-lymphocytes that are depleted ex vivo of their alloreactive component in the form of ATIR101 (Kiadis Pharma). Patient exposure to PTCy to eliminate donor alloreactive cells can be performed easily and at low cost but may cause patient toxicity and increase relapse rates, and it requires post-transplant immune suppression. Although ATIR101 requires cell manufacturing and is more expensive, it limits toxicity to the patient, enables haplo-HSCT without the use of immunosuppressants, and may reduce relapse rates. Both strategies are promising, but no attempt has yet been made to compare clinical results in similar patient populations to delineate key features of alloreactive T-cell depletion performed either ex vivo or in vivo. Methods: Data from published retrospective studies (single-site or registry data) were analyzed to assess clinical outcomes of haplo-HSCT plus PTCy. The 1-year outcomes from these studies were compared with results from a pooled analysis of 2 phase II clinical trials of a single dose of ATIR101 (N=37, all patients with AML/MDS/ALL [CR-AIR-007, CR-AIR-008]). Studies in which PTCy was used in patient populations with >50% AML/MDS/ALL were identified (Ciurea 2015, Piemontese 2017, Solomon 2012, Ciurea 2012, Devillier 2015, Di Stasi 2014, Esquirol 2016, Sugita 2015). The 1-year rates of relapse, relapse-related mortality (RRM), NRM, GVHD, and overall survival (OS) for the ATIR101 clinical trials were compared with the weighted average of these outcomes for the identified studies. OS is known to correlate with disease risk index (DRI; Armand 2014); therefore, publications reporting both OS and DRI (McCurdy 2017, Ciurea 2015, Devillier 2015, Sugita 2015) were identified to compare OS. Differences in DRI between PTCy and ATIR101 study populations were adjusted according to the relationship between DRI and OS. Finally, PTCy studies reporting GVHD-free and relapse-free survival (GRFS) were identified (Solh 2016, McCurdy 2017, Santoro 2017). There is a clinically relevant and statistically significant correlation between GRFS and DRI, so 1-year GRFS rates from the 2 studies reporting DRI status (Solh 2016, McCurdy 2017) were also normalized according to the DRI profile in the ATIR101 clinical trials to allow comparison. Results: The weighted average of PTCy (N=571) outcomes in populations with >50% AML/MDS/ALL vs ATIR101 patient outcomes were: 29% vs 8% for relapse; 18% vs 8% for RRM; 22% vs 33% for NRM; 5% vs 5% for acute GVHD grade III/IV; 24% vs 3% for chronic GVHD; and 60% vs 58% for OS. The OS in DRI-adjusted studies for PTCy (N=561) was similar to that in ATIR101 clinical trials (63% vs 58%, respectively). The GRFS-reporting studies included a total of 708 patients (Sohl 2016, N=128; McCurdy 2017, N=372; Santoro 2017, N=208); 1-year GRFS rates for PTCy in these studies were 33% (95% CI: 25-41), 45% (95% CI: 40-50), and 33% (average), respectively. In the 2 studies reporting DRI (N=500), the DRI profile was more favorable than in the ATIR101 studies and the 1-year GRFS rates normalized in line with the ATIR101 studies were reduced to 30% (Sohl 2016) and 40% (McCurdy 2017). In patients intended to receive a single dose of ATIR101 after haplo-HSCT, Kaplan-Meier estimate of 1-year GRFS was 53% (95% CI 39-72) (Table 1). Conclusion: This is not a head-to-head comparison, so data should be interpreted with caution. However, in these cross-study analyses, first insights into a potential advantage of ex vivo (ATIR101) over in vivo (PTCy) depletion of alloreactive T cells is suggested, including but not limited to rates of relapse, chronic GVHD, and GRFS. A large, phase III, randomized control trial is thus underway to assess the relative safety and efficacy of ATIR101 after T-cell-depleted haplo-HSCT versus PTCy after T-cell-replete haplo-HSCT (CR-AIR-009 HATCY; NCT02999854). Disclosures Devine: Kiadis Pharma: Consultancy. Mielke:Kiadis Pharma: Other: Travel grants, Research Funding. Tuk:Kiadis Pharma: Consultancy. Meewisse:Kiadis Pharma: Employment. Sandler:Kiadis Pharma: Employment. Roy:University of Montreal: Patents & Royalties: Author on patent; Kiadis Pharma: Other: Travel support; Hopital Maisonneuve Rosemont: Patents & Royalties: Author on patent.

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Overcoming Rejection of Bone Marrow Allografts by Treg Cells in a Stringent Mouse Model for T Cell Mediated Rejection: Tolerance Induction by Third Party “Off-the-Shelf” Cells.

Blood ◽

10.1182/blood.v106.11.576.576 ◽

2005 ◽

Vol 106 (11) ◽

pp. 576-576

Author(s):

David Steiner ◽

Noga Brunicki ◽

Esther Bachar-Lustig ◽

Yair Reisner

Keyword(s):

Bone Marrow ◽

T Cells ◽

T Cell ◽

Graft Rejection ◽

Ex Vivo ◽

Tolerance Induction ◽

Treg Cells ◽

Third Party ◽

Donor Type

Abstract Recent reports have shown that donor or host CD4+CD25+ Treg cells can be used to control GVHD or graft rejection following allogeneic BMT in mice. More recent data suggests that in the context of T cell depleted BM allografting, engraftment was only mildly improved by Treg cells alone, or by Rapamycin (RAPA) alone, but it was markedly enhanced by using Treg cells in conjunction with RAPA. These studies were carried out in a mouse model specifically designed to measure T cell mediated graft rejection. In this model, lethally irradiated (11Gy) C3H mice were infused with 1x104 purified host type T cells (HTC) and were transplanted one day later with 2x106 BM cells from Balb-Nude donors, which are markedly depleted of T cells and do not induce GVHD. Rejection mediated by the HTC is manifested by severe aplasia and lethality within 21 days posttransplant. In 10 independent experiments none of the mice in the irradiation control survived (0/62), the majority of the mice receiving BM survived (58/63) while marked rejection, associated with poor survival (2/62) was found in the group receiving purified HTC prior to the BM transplant. In the present study we further tested in this model whether third party Treg cells could be used instead of donor or host Treg cells to overcome rejection of BM allografts. We initially tested freshly isolated lymph node CD4+CD25+ cells. C3H (H2k) recipients received BM from Balb- Nude (H2d) donors and the Treg cells were obtained from Balb/c or FVB (H2q) donors. As in our previous study, while none of the recipients survived upon treatment with RAPA alone, using third party or donor type Treg cells in conjunction with RAPA led to survival of 9 of 13 and 7 of 10 mice respectively. Thus, the third party fresh Treg cells were as effective as the donor type cells in preventing graft rejection (P>0.05). Considering the low levels of CD4+CD25+ cells in peripheral blood or spleen, new strategies for growing these cells ex-vivo have been developed. Although, Treg cells exhibit low proliferative potential in-vitro upon TCR stimulation, the feasibility of growing mouse or human regulatory cells has been demonstrated mainly using the combination of TCR stimulation (either with an anti-TCR antibody or with allogeneic stimulator cells), costimulatory signals and high doses of IL-2. When tested in the same model, Treg cells ex-vivo expanded by stimulation against 4th party allogeneic cells, exhibited effective enhancement of engraftment of Balb-Nude BM. Thus, in four independent experiments, when assessing treatment with expanded Treg cells, of third party or donor type origin, the survival rate was 19 of 35 (54%) and 25 of 40 (62%) mice, respectively. Again, in both instances the marked potential of Treg cells to overcome T cell mediated rejection was exhibited only when co-administered with RAPA. In conclusion, our data strongly indicate that, at least in the bone marrow transplantation setting, third party Treg cells could afford a new viable ‘off-the-shelf’ source for tolerance induction. The use of third party Treg cells in contrast to donor type cells could allow advanced preparation of a large bank of Treg cells, with all the appropriate quality controls required for cell therapy. Further studies with human Treg cells in-vitro are required to ascertain the potential of third party cells as a valuable source for clinical transplantation.

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A GMCSF/Interleukin-15 Fusokine Leads to the Generation of a Novel Type of CD2/MHCII Immune Regulatory Cell with Potent Immune Suppressive Properties as Demonstrated in the EAE Mouse Model of Multiple Sclerosis.

Blood ◽

10.1182/blood.v110.11.2295.2295 ◽

2007 ◽

Vol 110 (11) ◽

pp. 2295-2295

Author(s):

Moutih Rafei ◽

Jeremy Hsieh ◽

Meng Yang Li ◽

Simone Zehntner ◽

Kathy Forner ◽

...

Keyword(s):

Multiple Sclerosis ◽

T Cells ◽

Autoimmune Disease ◽

Ex Vivo ◽

Regulatory Cell ◽

Autoreactive T Cell ◽

Experimental Allergic Encephalitis ◽

Over Time

Abstract Multiple sclerosis (MS) is an autoimmune disease characterised by the infiltration of autoreactive T-cell causing damages to the central nervous system. So far, interferon-β and glatiramer acetate are the only two immunomodulatory coumpounds that have been approved as non-curative disease managing strategies. Therefore, there is an urgent need for the development of novel efficient therapies that can be both safe and potent in inhibiting MS progression and promote reversal of disease state. We have recently published a report describing a novel synthetic GMCSF and IL15 Fusion Transgene (GIFT15) and have described its paradoxical and potent immune suppressive properties in vivo [Rafei et al., Blood (March 2007)]. Its mechanism of action relies on STAT3 hyperactivation arising from aberrant signalling taking place downstream of the IL15 receptor. We have now further studied the effect of GIFT15 on mouse spleen cells in vitro and here demonstrate that it leads to the conversion of murine T-cells to a novel suppressive regulatory cell type. Indeed, GIFT15-treated splenocytes (hereafter GIFT15 regs) shed their TCR and loose expression of CD3, CD4 and CD8, retain CD2 expression and acquire expression of MHC II. Distinct to classic T-regulatory cells, GIFT15 regs do not express CD25 or FOXP3. GIFT15 regs were able to suppress an in vitro two-way MLR by a contact-dependent mechanism as well as by the contemporaneous production of interleukin (IL)-10. Furthermore, GIFT15 regs were able to block antigen-specific activation of CD4-T-cells in response to autologous macrophage stimulation. As a proof-of-principle in vivo study, GIFT15 regs were injected intravenously in mice with pre-established experimental allergic encephalitis (EAE) and disease score was monitored over time. Interestingly, mice recovered significantly faster than controls following administration GIFT15 regs and a blockade in EAE progression was also noticed over time. In conclusion, our data suggests that GIFT15 can be used as a method to ex vivo generate suppressor cells of a new type which are distinct from classic Tregs or Tr1 cells. We propose that GIFT15 regs derived from autologous lymphocytes may be exploited for the treatment of autoimmune disease such as MS and may also be of use for other autoimmune ailments as well.

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Apoptosis of alloreactive T cells in liver allografts during tolerance induction

Transplantation Proceedings ◽

10.1016/s0041-1345(98)01714-x ◽

1999 ◽

Vol 31 (1-2) ◽

pp. 474 ◽

Cited By ~ 5

Author(s):

D Meyer ◽

M Thorwarth ◽

C Otto ◽

H.-J Gassel ◽

W Timmermann ◽

...

Keyword(s):

T Cells ◽

Tolerance Induction ◽

Alloreactive T Cells

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Idiopathic CD4 T Cell Lymphocytopenia: A Case of Overexpression of PD-1/PDL-1 and CTLA-4

Infectious Disease Reports ◽

10.3390/idr13010009 ◽

2021 ◽

Vol 13 (1) ◽

pp. 72-81

Author(s):

Gaurav Kumar ◽

Heidy Schmid-Antomarchi ◽

Annie Schmid-Alliana ◽

Michel Ticchioni ◽

Pierre-Marie Roger

Keyword(s):

T Cells ◽

T Cell ◽

Cd4 T Cells ◽

Ex Vivo ◽

Cd4 T Cell ◽

Apoptotic Pathway ◽

Cell Functions ◽

Inhibitory Molecules ◽

Cd4 T Cell Count ◽

Costimulatory Pathway

Idiopathic CD4 T cell lymphocytopenia (ICL) is a rare entity characterized by CD4 T cell count of <300 cells/mm3 along with opportunistic infection for which T cell marker expression remains to be fully explored. We report an ICL case for which T lymphocyte phenotype and its costimulatory molecules expression was analyzed both ex vivo and after overnight stimulation through CD3/CD28. The ICL patient was compared to five healthy controls. We observed higher expression of inhibitory molecules PD-1/PDL-1 and CTLA-4 on CD4 T cells and increased regulatory T cells in ICL, along with high activation and low proliferation of CD4 T cells. The alteration in the expression of both the costimulatory pathway and the apoptotic pathway might participate to down-regulate both CD4 T cell functions and numbers observed in ICL.

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