scholarly journals Caspase-8 deficiency in T cells leads to a lethal lymphoinfiltrative immune disorder

2005 ◽  
Vol 202 (6) ◽  
pp. 727-732 ◽  
Author(s):  
Leonardo Salmena ◽  
Razqallah Hakem

Caspase-8 is best known for its cell death function via death receptors. Recent evidence indicates that caspase-8 also has nonapoptotic functions. Caspase-8 deficiency is associated with pathologies that are unexpected for a proapoptotic molecule, such as abrogation of activation-induced lymphocyte proliferation, perturbed immune homeostasis, and immunodeficiency. In this study, we report the long-term physiological consequences of T cell–specific deletion of caspase-8 (tcasp8−/−). We show that tcasp8−/− mice develop an age-dependent lethal lymphoproliferative and lymphoinfiltrative immune disorder characterized by lymphoadenopathy, splenomegaly, and accumulation of T cell infiltrates in the lungs, liver, and kidneys. Peripheral casp8−/− T cells manifest activation marker up-regulation and are proliferating in the absence of any infection or stimulation. We also provide evidence suggesting that this immune disorder is different from the autoimmune lymphoproliferative syndrome. Interestingly, the condition described in tcasp8−/− mice manifests features consistent with the disorder described in humans with Caspase-8 deficiency. These findings suggest that tcasp8−/− mice may serve as an animal model to evaluate Caspase-8–deficient patient prognosis and therapy. Overall, our study uncovers novel in vivo functions for caspase-8 in immune regulation.

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Simone A Nish ◽  
Dominik Schenten ◽  
F Thomas Wunderlich ◽  
Scott D Pope ◽  
Yan Gao ◽  
...  

Innate immune recognition is critical for the induction of adaptive immune responses; however the underlying mechanisms remain incompletely understood. In this study, we demonstrate that T cell-specific deletion of the IL-6 receptor α chain (IL-6Rα) results in impaired Th1 and Th17 T cell responses in vivo, and a defect in Tfh function. Depletion of Tregs in these mice rescued the Th1 but not the Th17 response. Our data suggest that IL-6 signaling in effector T cells is required to overcome Treg-mediated suppression in vivo. We show that IL-6 cooperates with IL-1β to block the suppressive effect of Tregs on CD4+ T cells, at least in part by controlling their responsiveness to IL-2. In addition, although IL-6Rα-deficient T cells mount normal primary Th1 responses in the absence of Tregs, they fail to mature into functional memory cells, demonstrating a key role for IL-6 in CD4+ T cell memory formation.


Blood ◽  
2010 ◽  
Vol 115 (17) ◽  
pp. 3508-3519 ◽  
Author(s):  
John C. Markley ◽  
Michel Sadelain

Abstract The γc-cytokines are critical regulators of immunity and possess both overlapping and distinctive functions. However, comparative studies of their pleiotropic effects on human T cell–mediated tumor rejection are lacking. In a xenogeneic adoptive transfer model, we have compared the therapeutic potency of CD19-specific human primary T cells that constitutively express interleukin-2 (IL-2), IL-7, IL-15, or IL-21. We demonstrate that each cytokine enhanced the eradication of systemic CD19+ B-cell malignancies in nonobese diabetic/severe combined immunodeficient (NOD/SCID)/γcnull mice with markedly different efficacies and through singularly distinct mechanisms. IL-7– and IL-21–transduced T cells were most efficacious in vivo, although their effector functions were not as enhanced as IL-2– and IL-15–transduced T cells. IL-7 best sustained in vitro T-cell accumulation in response to repeated antigenic stimulation, but did not promote long-term T-cell persistence in vivo. Both IL-15 and IL-21 overexpression supported long-term T-cell persistence in treated mice, however, the memory T cells found 100 days after adoptive transfer were phenotypically dissimilar, resembling central memory and effector memory T cells, respectively. These results support the use of γc-cytokines in cancer immunotherapy, and establish that there exists more than 1 human T-cell memory phenotype associated with long-term tumor immunity.


2002 ◽  
Vol 22 (15) ◽  
pp. 5419-5433 ◽  
Author(s):  
Susanne M. A. Lens ◽  
Takao Kataoka ◽  
Karen A. Fortner ◽  
Antoine Tinel ◽  
Isabel Ferrero ◽  
...  

ABSTRACT The caspase 8 inhibitor c-FLIPL can act in vitro as a molecular switch between cell death and growth signals transmitted by the death receptor Fas (CD95). To elucidate its function in vivo, transgenic mice were generated that overexpress c-FLIPL in the T-cell compartment (c-FLIPL Tg mice). As anticipated, FasL-induced apoptosis was inhibited in T cells from the c-FLIPL Tg mice. In contrast, activation-induced cell death of T cells in c-FLIPL Tg mice was unaffected, suggesting that this deletion process can proceed in the absence of active caspase 8. Accordingly, c-FLIPL Tg mice differed from Fas-deficient mice by showing no accumulation of B220+ CD4− CD8− T cells. However, stimulation of T lymphocytes with suboptimal doses of anti-CD3 or antigen revealed increased proliferative responses in T cells from c-FLIPL Tg mice. Thus, a major role of c-FLIPL in vivo is the modulation of T-cell proliferation by decreasing the T-cell receptor signaling threshold.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 136-136
Author(s):  
M.M. van Loenen ◽  
R.S. Hagedoorn ◽  
M. Hoogeboom ◽  
M.G.D. Kester ◽  
Roelof Willemze ◽  
...  

Abstract TCR-transfer to engineer tumor-specific T cells may be a strategy for adoptive immunotherapy. For complete eradication of leukemic cells and to achieve long-term protection, potent effector T cell function and long-term T cell persistence are necessary. Therefore, we propose to use virus specific T cells for TCR transfer since such engineered dual specific T cells can be triggered via their endogenous TCR by latent presence of viral antigens, improving their long-term persistence. We have previously shown that virus specific T cells can be redirected towards anti-leukemic reactivity by transfer of the hematopoietic minor histocompatibility antigen HA-2 specific TCR (HA-2-TCR). The TCR-transferred virus specific T cells showed differences in TCR cell surface make up, which was stable for months after repetitive non-specific TCR triggering. The T cells expressed either both TCRs intermediately at the cell surface, or the endogenous TCR was highly expressed with a low expression of the introduced TCR, or the introduced TCR was highly expressed with a low expression of the endogenous TCR. It may be anticipated that frequent encounter with viral antigens in vivo leads to selective outgrowth of TCR-transferred dual specific T cells with high expression of the endogenous viral specific TCR but low expression of the introduced tumor specific TCR, resulting in reduced anti-leukemic reactivity. To address this issue, we generated CMVA2-specific T cells transduced with the HA-2-TCR. This resulted in dual specific cells with different TCR cell surface make up. The dual specific T cells were repetitively stimulated specifically either via their endogenous virus specific TCR or via the introduced HA-2 specific TCR. In time, the cell surface expression of the endogenous and introduced TCRs as measured with CMVA2 and HA-2A2 tetramers diverged. Repetitive stimulation of the endogenous TCR skewed the dual specific T cells towards a cell population that predominantly expressed the endogenous TCR. In contrast, repetitive stimulation of the introduced TCR skewed the cells towards T cells that predominantly expressed the introduced TCR. However, this divergence in tetramer stainings was shown to quickly revert after a single stimulation via the other TCR. To study whether this divergence was the result of a difference in TCR cell surface distribution or of selective outgrowth of different T cells, T cells were sorted that predominantly expressed either the endogenous or the introduced TCR. These cells were subsequently stimulated on the endogenous or introduced TCR, and compared regarding TCR cell surface expression and functional activity. Directly after sorting dual specific T cells preferentially expressing the endogenous TCR were still reactive against HA-2+ target cells, although the reactivity was reduced compared to cells preferentially expressing the introduced TCR. However, when restimulated on the introduced HA-2-TCR, the dual specific T cells expanded antigen specifically, and reverted within several days into cells with high expression of the introduced TCR that exerted potent HA-2 specific anti-leukemic effector functions. In conclusion, we demonstrate that these dual specific T cells are likely to persist in vivo due to repetitive encounter with viral antigens with preservation of anti-leukemic effector function. Moreover, in vivo exposure to the tumor associated antigen will further enhance the relevant specificity.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3249-3249
Author(s):  
Barbara Cassani ◽  
Grazia Andolfi ◽  
Massimiliano Mirolo ◽  
Luca Biasco ◽  
Alessandra Recchia ◽  
...  

Abstract Gene transfer into hematopoietic stem/progenitor cells (HSC) by gammaretroviral vectors is an effective treatment for patients affected by severe combined immunodeficiency (SCID) due to adenosine deaminase (ADA)-deficiency. Recent studied have indicated that gammaretroviral vectors integrate in a non-random fashion in their host genome, but there is still limited information on the distribution of retroviral insertion sites (RIS) in human long-term reconstituting HSC following therapeutic gene transfer. We performed a genome-wide analysis of RIS in transduced bone marrow-derived CD34+ cells before transplantation (in vitro) and in hematopoietic cell subsets (ex vivo) from five ADA-SCID patients treated with gene therapy combined to low-dose busulfan. Vector-genome junctions were cloned by inverse or linker-mediated PCR, sequenced, mapped onto the human genome, and compared to a library of randomly cloned human genome fragments or to the expected distribution for the NCBI annotation. Both in vitro (n=212) and ex vivo (n=496) RIS showed a non-random distribution, with strong preference for a 5-kb window around transcription start sites (23.6% and 28.8%, respectively) and for gene-dense regions. Integrations occurring inside the transcribed portion of a RefSeq genes were more represented in vitro than ex vivo (50.9 vs 41.3%), while RIS <30kb upstream from the start site were more frequent in the ex vivo sample (25.6% vs 19.4%). Among recurrently hit loci (n=50), LMO2 was the most represented, with one integration cloned from pre-infusion CD34+ cells and five from post-gene therapy samples (2 in granulocytes, 3 in T cells). Clone-specific Q-PCR showed no in vivo expansion of LMO2-carrying clones while LMO2 gene overexpression at the bulk level was excluded by RT-PCR. Gene expression profiling revealed a preference for integration into genes transcriptionally active in CD34+ cells at the time of transduction as well as genes expressed in T cells. Functional clustering analysis of genes hit by retroviral vectors in pre- and post-transplant cells showed no in vivo skewing towards genes controlling self-renewal or survival of HSC (i.e. cell cycle, transcription, signal transduction). Clonal analysis of long-term repopulating cells (>=6 months) revealed a high number of distinct RIS (range 42–121) in the T-cell compartment, in agreement with the complexity of the T-cell repertoire, while fewer RIS were retrieved from granulocytes. The presence of shared integrants among multiple lineages confirmed that the gene transfer protocol was adequate to allow stable engraftment of multipotent HSC. Taken together, our data show that transplantation of ADA-transduced HSC does not result in skewing or expansion of malignant clones in vivo, despite the occurrence of insertions near potentially oncogenic genomic sites. These results, combined to the relatively long-term follow-up of patients, indicate that retroviral-mediated gene transfer for ADA-SCID has a favorable safety profile.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 866-866
Author(s):  
Carolina Berger ◽  
Michael C. Jensen ◽  
Stanley R. Riddell

Abstract Adoptive transfer of T cells has been employed to reconstitute T cell immunity to viruses such as cytomegalovirus (CMV) in immunodeficient allogeneic stem cell transplant (SCT) patients and is being investigated to treat malignancies. In the allogeneic SCT setting, the T cells are derived from the donor and need to be isolated as clones or highly pure populations to avoid graft-versus-host disease. CD8+ T cells can be divided into defined subsets including CD62L− effector memory (TEM) and central memory T cells (TCM) expressing the CD62L lymph node homing molecule. Both TCM and TEM can give rise to cytolytic effector T cells (TE) after antigen stimulation and can be expanded in vitro for immunotherapy. However, the potential of T cells derived from either the TEM or TCM subset to persist in vivo has not been investigated. We used a macaque model to determine whether reconstitution of T cell memory to CMV by adoptive transfer of CD8+ T cell clones depended on their origin from either the CD62L+ TCM or CD62L− TEM subset. T cell clones were retrovirally transduced to express the macaque CD19 or CD20 surface marker to allow tracking of T cells in vivo. Clones derived from both TCM and TEM had similar avidity and proliferative capacity in vitro, and had a TE phenotype (CD62L−CCR7−CD28−CD127−, granzyme B+). TCM and TEM-derived T cell clones were transferred to macaques at doses of 3–6×108/kg and were both detected in the blood one day after transfer at 1.2–2.7% (low dose) to 20–25% (high dose) of CD8+ T cells. However, the frequency of TEM-derived T cells was undetectable after 3–5 days, and the cells were not present in lymph node or bone marrow obtained at day 14. By contrast, TCM-derived clones persisted in peripheral blood, migrated to tissue sites, and were detectable long-term at significant levels. A distinguishing feature of TCM-derived cells was their responsiveness to homeostatic cytokines. Only TCM-derived clones were rescued from apoptotic cell death by low-dose IL15 for &gt;30 days in vitro and this correlated with higher levels of IL15Rα, IL2Rβ, and IL2Rγ, and of Bcl-xL and Bcl-2, which promote cell survival. To determine if the inability of TEM-derived clones to survive in vitro correlated with an increased susceptibility of cell death in vivo, we measured the proportion of infused cells that were positive for propidium iodide (PI) and Annexin V during the short period of in vivo persistence. One day after transfer, 41–45% of TEM-derived T cells were Annexin V+/PI+, analyzed directly in the blood or after 24 hours of culture. By contrast, only a minor fraction of an adoptively transferred TCM-derived T cell clone was Annexin V+/PI+ and the infused cells survived in vivo. A subset of the persisting T cells reacquired TCM marker (CD62L+CCR7+CD127+CD28+) in vivo and regained functional properties of TCM (direct lytic activity; rapid proliferation to antigen). These T cells produced IFN-γ and TNF-α after peptide stimulation, and studies are in progress to assess their in vivo response to antigen by delivery of T cells expressing CMV proteins. Our studies in a large animal model show for the first time that CD8+ TE derived from TCM but not TEM can persist long-term, occupy memory T cell niches, and restore TCM subsets of CMV-specific immunity. Thus, taking advantage of the genetic programming of cells that have become TCM might yield T cells with greater therapeutic activity and could be targeted for human studies of T cell therapy for both viral and malignant disease.


Blood ◽  
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 ◽  
...  

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.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 380-380 ◽  
Author(s):  
Stephan A. Grupp ◽  
Shannon L Maude ◽  
Pamela Shaw ◽  
Richard Aplenc ◽  
David M. Barrett ◽  
...  

Abstract BACKGROUND CARs combine a single chain variable fragment (scFv) of an antibody with intracellular signaling domains. We have previously reported on CTL019 cells expressing an anti-CD19 CAR. Infusion of these cells results in 100 to 100,000x in vivo proliferation, durable anti-tumor activity, and prolonged persistence in pts with B cell tumors, including sustained CRs in adults and children with ALL (Grupp et al., NEJM 2013, Maude et al., NEJM 2014). We now report on outcomes and longer follow up of the first 30 pts with relapsed, refractory ALL treated on our pilot trial in pediatric ALL. METHODS T cells were lentivirally transduced with a CAR composed of anti-CD19 scFv/4-1BB/CD3ζ, activated/expanded ex-vivo with anti-CD3/anti-CD28 beads, and then infused into children with relapsed or refractory CD19+ ALL. 26/30 pts received lymphodepleting chemotherapy the week prior to CTL019 infusion. The targeted T cell dose range was 107 to 108 cells/kg with a transduction efficiency of 11-45%. T cells for manufacturing were collected from the pt regardless of prior SCT status, not allo donors. RESULTS 30 children median age 10y (5-22y) with CD19+ ALL were treated. 25/30 pts had detectable disease on the day before CTL019 cell infusion, while 5 were MRD(-). A median of 3.6x106 CTL019 cells/kg (1.1-18x106/kg) were infused over 1-3 days. There were no infusional toxicities >grade 2, although 9 pts developed fevers within 24 hrs of infusion and did not receive a planned 2nd infusion of CTL019 cells. 27 pts (90%) achieved a CR, including a patient with T cell ALL aberrantly expressing CD19+. 3 did not respond. MRD measured by clinical flow cytometry was negative in 23 responding pts and positive at 0.1% (negative at 3 mo), 0.09%, 0.22%, and 1.1% in 4 pts. With median follow up 8 mo (1-26 mo), 16 pts have ongoing CR, with only 3 patients in the cohort receiving subsequent treatment such as donor lymphocyte infusion or SCT, 6-month EFS measured from infusion is 63% (95% CI, 47-84%), and OS is 78% (95% CI, 63-95%). CTL019 cells were detected in the CSF of 17/19 pts and 2 pts with CNS2a disease experienced a CR in CSF. 10 pts with a CR at 1 mo have subsequently relapsed, half with CD19(-) blasts. 2/5 pts who relapsed with CD19(-) disease had previously been refractory to CD19-directed blinatumomab and subsequently went into CR with CTL019. Figure 1 Figure 1. All responding pts developed grade 1-4 cytokine release syndrome (CRS) at peak T cell expansion. Detailed cytokine analysis showed marked increases of IL6 and IFNγ (both up to 1000x), and IL2R. Treatment for CRS was required for hemodynamic or respiratory instability in 37% of patients and was rapidly reversed in all cases with the IL6-receptor antagonist tocilizumab, together with corticosteroids in 5 pts. Although T cells collected from the 21 pts who had relapsed after allo SCT were median 100% donor origin, no GVHD has been seen. Grade 4 CRS was strongly associated with high disease burden prior to infusion and with elevations in IL-6, ferritin (suggesting macrophage activation syndrome) and C reactive protein after infusion. Persistence of CTL019 cells detected by flow cytometry and/or QPCR, and accompanied by B cell aplasia, continued for 1-26 months after infusion in pts with ongoing responses. QPCR showed very high levels of CTL019 proliferation, with all patients achieving peak levels >5000 copies/ug gDNA and 26 patients with peak levels >15,000 copies/ug gDNA. B cell aplasia has been treated with IVIg without significant infectious complications. Probability of 6-mo CTL019 persistence by flow was68% (95% CI, 50-92%) andrelapse-free B cell aplasia was 73% (95% CI, 57-94%). CONCLUSIONS: CTL019 cells can undergo robust in-vivo expansion and can persist for 2 years or longer in pts with relapsed ALL, allowing for the possibility of long-term disease response without subsequent therapy such as SCT. This approach also has promise as a salvage therapy for patients who relapse after allo-SCT with a low risk of GVHD. CTL019 therapy is associated with a significant CRS that responds rapidly to IL-6-targeted anti-cytokine treatment. CTL019 cells can induce potent and durable responses for patients with relapsed/refractory ALL; however, recurrence with cells that have lost CD19 is an important mechanism of CLT019 resistance. CTL019 therapy has received Breakthrough Therapy designation from the FDA in both pediatric and adult ALL, and phase II multicenter trials have been initiated. Disclosures Grupp: Novartis: Consultancy, Research Funding. Barrett:Novartis: Research Funding. Chew:Novartis: Research Funding. Lacey:Novartis: Research Funding. Levine:Novartis: Patents & Royalties, Research Funding. Melenhorst:Novartis: Research Funding. Rheingold:Novartis: Consultancy. Shen:Novartis: Employment. Wood:Novartis Pharma: Employment. Porter:Novartis: managed according to U Penn Policy Patents & Royalties, Research Funding. June:Novartis: Research Funding, Royalty income Patents & Royalties.


2004 ◽  
Vol 78 (21) ◽  
pp. 11641-11647 ◽  
Author(s):  
Hong He ◽  
Ronald J. Messer ◽  
Shimon Sakaguchi ◽  
Guojun Yang ◽  
Shelly J. Robertson ◽  
...  

ABSTRACT Chronic infection with Friend retrovirus is associated with suppressed antitumor immune responses. In the present study we investigated whether modulation of T-cell responses during acute infection would restore antitumor immunity in persistently infected mice. T-cell modulation was done by treatments with DTA-1 anti- glucocorticoid-induced tumor necrosis factor receptor monoclonal antibodies. The DTA-1 monoclonal antibody is nondepleting and delivers costimulatory signals that both enhance the activation of effector T cells and inhibit suppression by regulatory T cells. DTA-1 therapy produced faster Th1 immune responses, significant reductions in both acute virus loads and pathology and, most importantly, long-term improvement of CD8+ T-cell-mediated antitumor responses.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 841-841
Author(s):  
Jooho Chung ◽  
Christen L. Ebens ◽  
Vedran Radojcic ◽  
Ute Koch ◽  
Ann Friedman ◽  
...  

Abstract Notch signaling is a critical regulator of T cell effector functions during acute graft-versus-host disease (GVHD). Pan-Notch inhibition in donor-derived T cells or systemic antibody-mediated blockade of Delta-like1 (Dll1) and Delta-like4 (Dll4) Notch ligands results in near-complete protection from acute GVHD in mouse models of allogeneic bone marrow transplantation. Notch-deprived alloreactive T cells proliferate and accumulate in vivo, but produce dramatically reduced levels of the proinflammatory cytokines IFNγ, TNFα and interleukin-2 (IL-2) (Zhang et al., Blood 2011; Sandy et al., J Immunol 2013; Tran et al., J Clin Invest 2013). In this study, we sought to: 1) determine the kinetic requirements for Notch signaling in the pathogenesis of acute GVHD; 2) identify the essential cellular compartment that delivers Dll1 and/or Dll4 ligands to incoming alloreactive T cells. In the B6 anti-BALB/c major histocompatibility complex-mismatched model, a single dose of Dll1 and Dll4 blocking antibodies at the time of transplantation abolished alloreactive T cell production of IFNγ, TNFα, and IL-2, increased regulatory T cell numbers (as assessed at day 10), and conferred long-term protection from GVHD. Conversely, delaying antibody administration by only two days after transplantation resulted in persistent T cell cytokine production, no changes in regulatory T cell numbers, and loss of long-term protection from GVHD. These findings identify a critical early window of Notch activity that promotes the pathogenesis of acute GVHD. To identify the dominant cellular source of Dll1 and Dll4, we assessed the impact of Cre-mediated Dll1 and Dll4 inactivation within host hematopoietic, donor hematopoietic, or host non-hematopoietic tissues. Bone marrow chimeras that lacked Dll1 and Dll4 solely within the host hematopoietic system were generated from poly(I:C)-induced Mx1-Cre;Dll1fl/fl;Dll4fl/fl donor mice. Both donor chimerism and Cre-mediated excision efficiency were >97%. Unlike systemic Dll1/4 blockade, Dll1 and Dll4 inactivation within the host hematopoietic system failed to decrease GVHD mortality or severity. Likewise, Mx1-Cre-mediated deletion of Dll1 and Dll4 within the donor hematopoietic system had minimal effects on T cell proinflammatory cytokines. In contrast, Ccl19-Cre-mediated Dll1 and Dll4 inactivation within host stromal cells profoundly impaired donor T cell production of IFNγ, TNFα, and IL-2, and resulted in long-term protection from GVHD. Lineage tracing in Ccl19-Cre x ROSA26-YFP mice revealed Cre activity within a small subset of CD45-negative lymph node and spleen stromal cells, but not in professional hematopoietic antigen-presenting cells. These data suggest that a specialized subset of non-hematopoietic stromal cells delivers an early pulse of Notch signaling to alloreactive T cells during acute GVHD. To our knowledge, these results provide the first in vivo evidence for non-motile secondary lymphoid-resident stromal cells as critical drivers of T cell-mediated immune pathology, with a central role for Notch signaling in this process. Transient interference with Notch ligand function or with their expression by the stromal cell niche in the peri-transplant period could serve as a novel therapeutic strategy for GVHD. Disclosures Yan: Genentech: Employment, Equity Ownership. Siebel:Genentech: Employment, Equity Ownership.


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