scholarly journals MHC Class II on Ccl19+ Reticular Cells Mitigates Graft-Versus-Host Disease Via Maintenance of Regulatory T Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 23-23
Author(s):  
Muhammad Haroon Shaikh ◽  
Juan Gamboa Vargas ◽  
Josefina Peña Mosca ◽  
Duc Dung Le ◽  
Hermann Einsele ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Research Funding ◽  
Class Ii ◽  
Graft Versus Host ◽  
Alloreactive T Cells ◽  
Reticular Cells

Allogeneic T cell priming is considered as an essential event determining the outcome of allogeneic hematopoietic stem cell transplantation (allo-HCT), ideally triggering anti-leukemic responses (GvL effect) or, at worst, causing life-threatening acute graft-versus-host disease (aGvHD). During aGvHD initiation, alloreactive T cells are activated by host antigen presenting cells (APCs), rapidly expand and subsequently exert tissue damage. Recently, it was discovered that in absence of host hematopoietic APCs, aGvHD cannot be prevented, suggesting a crucial role of non-hematopoietic APCs for priming alloreactive T cells (Toubai et al., Blood 2012, Li et al., J Immunol. 2012, Koyama et al., Nat Med 2012). However, the exact location and identity of host non-hematopoietic APCs triggering alloreactive T cell responses remains controversial and needs to be proven in vivo. Fibroblastic reticular cells (FRCs) have shown to provide the crucial delta-like notch ligand to alloreactive T cells (Chung et al., JCI 2017) in aGvHD, therefore we investigated the role of FRCs MHC class II in aGvHD and their potential role as non-hematopoietic APCs in MHC class II dependent manner. In vitro cultured FRCs cell line as well as FRCs from lethally irradiated mice upregulate MHCII and co-stimulatory molecules. Moreover, FACS sorted FRCs (CD45-CD24-CD31-gp38+) were able to process DQ-OVA via MHC class II machinery, indicating that FRCs have the potential to activate CD4+ T cells. Employing allo-HCT mouse models in combination with flow cytometry and advanced microscopy techniques, we explored early alloreactive T cells activation initially in a myeloablatively conditioned MHC major mismatch allo-HCT setting (FVB/NàC57Bl/6). We generated MHCIIΔCcl19 mice with a Ccl19-intrinsic deletion of MHC class II on all Ccl19 expressing reticular lineage cells by crossing mice with floxed H2-Ab1 gene (H2-Ab1fl) with a mouse expressing Cre recombinase under the control of the Ccl19 promoter (Ccl19Cre). On day+3 after allo-HCT, CD4+ T cells activation (CD44 and CD25 expression) and proliferation (Ki67 expression and CFSE dilution) did not differ in the MHCIIΔCcl19 mice from H2-Ab1fl wildtype littermates. To further elucidate FRCs MHC class II in aGvHD milieu, we utilized iFABP-tOVA transgenic model in which OVA is expressed by intestinal epithelial cells as well as ectopically by FRCs of the lymphoid organs. OT-II cells transferred from RagΔ background mice failed to proliferate in the mLNs of lethally irradiated iFABP-tOVA, whereas excessive proliferation was observed in CD11c.DOG mice (where OVA is presented by CD11c-expressing cells). Taken together these results indicate that MHCII on FRCs does not play a role in direct antigen presentation and CD4+ T cell activation. Next, we asked whether MHCII on FRCs influences alloreactivity of CD4+ T cells in the symptomatic phase of aGvHD. Indeed, in MHCIIΔCcl19 mice, CD4+ T cells expressed higher levels of effector molecules: CD44 and CD127 as well as the proliferation marker Ki67 on day +30 of allo-HCT. Furthermore, the proportion of donor CD90.1+CD4+FoxP3+ regulatory T cells (Tregs) were reduced in MHCIIΔCcl19 mice as compared to H2-Ab1fl wild-type littermates. This led to overall poor survival of MHCIIΔCcl19 mice by day+60 after allo-HCT. At this time point in MHCIIΔCcl19 mice CD4+ T cells displayed higher levels of CD44, CD127 and Ki67 and down-regulated PD-1 and Lag3. To further elucidate the effect of FRCs MHC class II on CD4+FoxP3+ donor Tregs, we transplanted CD90.1+CD4+CD25hi Tregs, TCD BM from FVB mice along with naïve luc+ CD90.1+CD4+ T cells from FVB.L2G85 mice. Tregs protected against aGvHD in H2-Ab1fl littermate controls whereas Tregs could not protect MHCIIΔCcl19 recipients rendering them susceptible to aGvHD and to poor overall survival. Conclusively, these results indicate for the first time that MHC class II on FRCs assists to maintain donor Tregs in the SLOs after allo-HCT. Conclusively, we propose a model in which FRCs promote T cell alloreactivity by providing notch ligands (Chung et al., JCI 2017) in the initiation phase and mitigate aGvHD by maintenance of Tregs via MHC class II in the aGvHD-effector phase. Disclosures Einsele: Janssen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy, Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau; Takeda: Consultancy, Honoraria, Speakers Bureau; Sanofi: Consultancy, Honoraria, Research Funding, Speakers Bureau; GlaxoSmithKline: Honoraria, Research Funding, Speakers Bureau.

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

Blood ◽  
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.

Self-recognition is crucial for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment

Blood ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 270-277 ◽  
Author(s):  
Bruno Martin ◽  
Chantal Bécourt ◽  
Boris Bienvenu ◽  
Bruno Lucas
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Cell Pool ◽  
Self Recognition ◽  
Mhc Class Ii Molecules

The role of self-recognition in the maintenance of the peripheral CD4+ T-cell pool has been extensively studied, but no clear answer has so far emerged. Indeed, in studies of the role of self-major histocompatibility complex (MHC) molecules in CD4+ T-cell survival, several parameters must be taken into account when interpreting the results: (1) in a lymphopenic environment, observations are biased by concomitant proliferation of T cells arising in MHC-expressing mice; (2) the peripheral T-cell compartment is qualitatively and quantitatively different in nonlymphopenic, normal, and MHC class II-deficient mice; and (3) in C57BL/6 Aβ-/- mice (traditionally considered MHC class II-deficient), the Aα chain and the Eβ chain associate to form a hybrid AαEβ MHC class II molecule. In light of these considerations, we revisited the role of interactions with MHC class II molecules in the survival of peripheral CD4+ T cells. We found that the answer to the question “is self-recognition required for CD4+ T cells to survive?” is not a simple yes or no. Indeed, although long-term survival of CD4+ T cells does not depend on self-recognition in lymphopenic mice, interactions with MHC class II molecules are required for maintaining the peripheral CD4+ T-cell pool in a nonlymphopenic environment. (Blood. 2006;108:270-277)

KEL RBC Transfusion Induces IgG Anti-KEL Antibodies Independent Of CD4 T Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 41-41 ◽  
Author(s):  
Sean R. Stowell ◽  
Kathryn R. Girard-Pierce ◽  
Connie M Arthur ◽  
Nicole H. Smith ◽  
James C. Zimring ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Potential Role ◽  
Class Ii ◽  
Cd4 T Cell ◽  
Isotype Control ◽  
Rbc Transfusion

Abstract Background While red blood cells (RBCs) transfusion can provide life saving therapy, patients who require chronic transfusion therapy may develop RBC alloantibodies that limit the availability of compatible RBCs for future transfusion and increase the risk of hemolytic transfusion reactions. However, not all patients generate alloantibodies following RBC exposure. Among factors that potentially influence RBC alloantibody formation, several studies suggest that a recipient’s MHC class II repertoire may predict an individual’s likelihood of responding to a particular RBC alloantigen. However, whether MHC class II antigens are required for efficient alloantibody formation following RBC transfusion remains unknown. As a result, we examined the potential role of MHC class II in the development of RBC alloantibodies following transfusion in a murine model of KEL alloimmunization. Methods RBCs transgenically expressing the human KEL antigen specifically under a β-globin promoter (KEL RBCs) were transfused into C57BL/6, C57BL/6 MHC class II knock out (KO) or KEL transgenic control recipients. Following transfusion, blood was harvested on days 3, 5, 7, 14, 21 and 28 following transfusion and serum was analyzed for IgM or IgG anti-KEL antibodies by indirect immunofluorescence using flow cytometry with KEL and control C57BL/6 RBCs as targets. To deplete CD4 T cells, mice were injected with anti-CD4 (clone GK1.5) 4 and 2 days prior to transfusion. As a control, additional C57BL/6 recipients were similarly injected with an isotype control. C57BL/6 recipients were also injected in parallel with GK1.5 or isotype control followed by splenocyte examination for CD4 T cell depletion using anti-CD3 and an anti-CD4 clone that recognizes a different CD4 epitope than GK1.5 (clone RM4-5). All experiments were completed at least three times with 3–5 recipients per group per experiment. Results Transfusion of KEL RBCs resulted in significant IgM anti-KEL antibody formation that peaked approximately 5 days following transfusion in both C57BL/6 and C57BL/6 MHC class II KO recipients. Similarly, IgG anti-KEL antibodies could also be detected in C57BL/6 or C57BL/6 MHC class II KO as early as 7 days following transfusion and continued to rise to similar peak levels within 14 to 21 days following KEL RBC transfusion. Injection of GK1.5, but not isotype control antibody, depleted CD4 T cells to less than 1% of their original level. Transfusion of KEL RBCs into C57BL/6, CD4 depleted C57BL/6 or isotype control treated C57BL/6 resulted in similar levels of IgM anti-KEL antibody that peaked approximately 5 days following transfusion. Likewise, transfusion of KEL RBCs induced similar levels of IgG anti-KEL antibodies within 7 days following transfusion that also peaked between 14 and 21 days in C57BL/6, CD4 depleted C57BL/6 or isotype control treated C57BL/6 recipients. (All the above differences achieved a p value of <0.05) Conclusions Despite the potential role of CD4 T cells in facilitating RBC alloantibody formation, these results suggest that significant IgG RBC alloantibody can occur independent of MHC class II or CD 4 T cells. Although it remains possible that CD4 T cells become activated following RBC alloantigen exposure, the lack of CD4 T cell requirement in this model suggests that some patients may be capable of mounting a clinically significant immune response following RBC transfusion in the absence of CD4 T cell help. As a result, MHC antigen presentation of unique RBC alloantigens may not be necessary for RBC alloimmunization to occur. Disclosures: Zimring: Immucor Inc.: Research Funding; Terumo: Research Funding; Haemonetics: Consultancy; Cerus: Honoraria.

Induction and Break of Immune Tolerance to Human FVIII in a HLA-DRB1*1501 Humanized Hemophilic Mouse Model

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2280-2280
Author(s):  
Katharina Nora Steinitz ◽  
Brigitte Binder ◽  
Christian Lubich ◽  
Rafi Uddin Ahmad ◽  
Markus Weiller ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Mouse Model ◽  
Mhc Class Ii ◽  
Immune Tolerance ◽  
Cd4 T Cells ◽  
Hemophilia A ◽  
Class Ii ◽  
T Cell Epitopes

Abstract Abstract 2280 Development of neutralizing antibodies against FVIII is the major complication in the treatment of patients with hemophilia A. Although several genetic and environmental risk factors have been identified, it remains unclear why some patients develop antibodies while others do not. Understanding the underlying mechanisms that drive the decision of the immune system whether or not to make antibodies against FVIII would help to design novel therapeutics. We used a new humanized hemophilic mouse model that expresses the human MHC-class II molecule HLA-DRB1*1501 on the background of a complete knock out of all murine MHC-class II genes. Initial studies had indicated that only a fraction of these mice developed antibodies when intravenously (i.v.) treated with human FVIII. These findings which resemble the situation in patients with severe hemophilia A, evoked the question if the lack of antibody development in non-responder mice reflects the induction of specific immune tolerance after i.v. application of FVIII or represent non-responsiveness for other reasons. We addressed this question by choosing another application route (subcutaneous, s.c.) and by combining i.v. application with a concomitant activation of the innate immune system applying LPS, a well characterized ligand for toll-like receptor 4, together with FVIII. Both strategies resulted in the development of antibodies in all mice included in the study what suggested that non-responsiveness against i.v. FVIII does not reflect an inability to develop antibodies against FVIII. Next, we asked if i.v. FVIII does induce immune tolerance in non-responder mice. We pretreated mice with i.v. FVIII, selected non-responder mice and challenged them with s.c. FVIII. None of the mice developed antibodies what indicated that i.v. pretreatment had induced immune tolerance in non-responder mice. Currently, we test the hypothesis that immune tolerance after i.v. application is induced and maintained by FVIII-specific regulatory T cells. The differences in responder rates after i.v. and s.c. application of FVIII raised the question if there are differences in FVIII T-cell epitopes involved in the initial activation of FVIII-specific CD4+ T cells. We obtained spleen cells from mice treated with either i.v. or s.c. FVIII and generated CD4+ T-cell hybridoma libraries that were tested for peptide specificities. For this purpose we used a FVIII peptide library containing 15 mers with an offset of 3 amino acids. Our results indicate that the pattern of FVIII-specific T-cell epitopes involved in the activation of FVIII-specific CD4+ T cells after i.v. and s.c. application of FVIII is almost identical and represents a small set of FVIII peptides distributed over the A1, A2, B, A3 and C1 domains. Based on our results we conclude that the new HLA-DRB1*1501 hemophilic mouse model represents an interesting opportunity to uncover the mechanisms that drive the decision of the immune system whether or not to develop antibodies against FVIII. Disclosures: Steinitz: Baxter BioScience: Employment. Binder:Baxter BioScience: Employment. Lubich:Baxter BioScience: Employment. Ahmad:Baxter BioScience: Employment. Weiller:Baxter BioScience: Employment. de la Rosa:Baxter BioScience: Employment. Schwarz:Baxter BioScience: Employment. Scheiflinger:Baxter BioScience: Employment. Reipert:Baxter Innovations GmbH: Employment.

Role of MHC class II expressing CD4+ T cells in proteolipid protein91–110-induced EAE in HLA-DR3 transgenic mice

2006 ◽  
Vol 36 (12) ◽  
pp. 3356-3370 ◽  
Author(s):  
Ashutosh Mangalam ◽  
Moses Rodriguez ◽  
Chella David
Keyword(s):  
T Cells ◽  
Transgenic Mice ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Hla Dr3

scholarly journals Endogenous human cytomegalovirus gB is presented efficiently by MHC class II molecules to CD4+ CTL

2005 ◽  
Vol 202 (8) ◽  
pp. 1109-1119 ◽  
Author(s):  
Nagendra R. Hegde ◽  
Claire Dunn ◽  
David M. Lewinsohn ◽  
Michael A. Jarvis ◽  
Jay A. Nelson ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Glial Cells ◽  
Human Cytomegalovirus ◽  
Cd4 T Cells ◽  
Class Ii ◽  
Host Cells ◽  
Cd4 T Cell

Human cytomegalovirus (HCMV) infects endothelial, epithelial, and glial cells in vivo. These cells can express MHC class II proteins, but are unlikely to play important roles in priming host immunity. Instead, it seems that class II presentation of endogenous HCMV antigens in these cells allows recognition of virus infection. We characterized class II presentation of HCMV glycoprotein B (gB), a membrane protein that accumulates extensively in endosomes during virus assembly. Human CD4+ T cells specific for gB were both highly abundant in blood and cytolytic in vivo. gB-specific CD4+ T cell clones recognized gB that was expressed in glial, endothelial, and epithelial cells, but not exogenous gB that was fed to these cells. Glial cells efficiently presented extremely low levels of endogenous gB—expressed by adenovirus vectors or after HCMV infection—and stimulated CD4+ T cells better than DCs that were incubated with exogenous gB. Presentation of endogenous gB required sorting of gB to endosomal compartments and processing by acidic proteases. Although presentation of cellular proteins that traffic into endosomes is well known, our observations demonstrate for the first time that a viral protein sorted to endosomes is presented exceptionally well, and can promote CD4+ T cell recognition and killing of biologically important host cells.

scholarly journals β2- Adrenergic Signaling Regulates Graft Versus Host Disease after Allogenic Transplantation While Preserving Graft Versus Leukemia Effect

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 1915-1915 ◽  
Author(s):  
Hemn Mohammadpour ◽  
Joseph L. Sarow ◽  
George L. Chen ◽  
Cameron R. MacDonald ◽  
Umesh Sharma ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Adrenergic Receptor ◽  
Graft Versus Host ◽  
Graft Versus Leukemia ◽  
Donor T Cells ◽  
Β2 Adrenergic Receptor ◽  
Ifn Γ

β2 adrenergic receptor signaling is a key regulator of various immune cells, including T cells; however, its role in T cell function in the context of graft versus host disease (GvHD) is poorly understood. We previously showed that housing mice at thermoneutral temperature (TT; 30°C), which reduces systemic adrenergic stress, increased the incidence and severity of GvHD after allogeneic hematopoietic cell transplant (allo-HCT) compared to mice housed at standard temperature (ST; 22°C) which exerts a mild but chronic adrenergic stress (Leigh et al J Immunol 2015). The increased incidence and severity of GvHD in TT mice can be reversed by the administration of a β2-adrenergic receptor (β2-AR) agonist, suggesting an important role of epinephrine and norepinephrine in allo-HCT outcome (Leigh et al., J. Immunol 2015; Mohammadpour et al J Immunol 2018). We investigated the mechanisms and downstream events of β2-AR signaling in donor T cells after allo-HCT by using β2-AR knockout (β2-AR-/-) mice and commercially available β2-AR agonists. The main goal here was to explore whether signaling through β2-AR in donor T cells could control GvHD incidence and severity without minimizing the graft-versus leukemia (GvL) effect. We utilized both a major MHC-mismatch C57B6 (H-2kb) into BALB/c (H-2kd) model and a MHC-matched, multiple minor histocompatibility antigen (miHA) mismatched B6 (H-2kb) into C3H/SW (H-2kb) model. Recipient BALB/c and C3H/SW WT mice were lethally irradiated with 850 and 1100 cGy respectively and injected by tail vein with T cell depleted bone marrow (TCD-BM) alone (3 ×106) or TCD-BM and splenic T cells derived from allogeneic WT or β2-AR-/- B6 donors (0.7 × 106 T cells in B6 → BALB/c and 1.5 × 106 in B6 → C3H/SW). We found that donor T cells express β2-AR after allo-HCT and that β2-AR expression on WT T cells plays an important role in controlling GvHD, as evidenced by less severe weight loss, and increased survival compared to mice receiving β2-AR-/- donor T cells (Figure 1A). Histopathologic examination showed that β2-AR-/- T cells induced more damage in the small and large intestine. To explore further the mechanism(s) by which β2-AR signaling controls the severity of GvHD, we used NanoString analysis and discovered that β2-AR-/- T cells have the Th1 phenotype with an increase in Tbx21, Ifng, Irf8 and Emoes genes, while WT CD4+ T cells had higher levels of Th2 and Treg associated genes, including Foxp3, Ptgs5, Tgfb2, Il10, Il21 and Il22. We also observed a significant increase in the inflammatory cytokines IFN-γ and IL-17 in β2-AR-/- CD4+ T cells from the spleen and liver on days 7 and 14 after allo-HCT as compared to WT T cells (Figure 1B), while the expression of IL-10 was significantly higher in WT T cells compared to β2-AR-/- T cells (P< 0.01). We next sought to determine whether GvL may be affected by use of long acting β2-AR agonist (Bambuterol) to control GvHD. Bambuterol was administered daily at a dose of 1mg/kg from day 0. We observed that Bambuterol controlled the severity and mortality of GvHD after allo-HCT in both major and minor mismatch mouse models, as evidenced by reduced weight loss and an improved clinical score and survival rate in mice receiving Bambuterol compared to vehicle (P<0.001). We showed that treatment increased the expression of IL-10 and decreased the expression of IFN-γ and IL-17 in CD4+ T cells. Interestingly, we found that β2-AR agonist treatment significantly increased the generation of myeloid derived suppressor cells (MDSCs) from WT BM without any effect on β2-AR-/- BM both in vitro and in vivo, suggesting an important role of β2-AR signaling in the generation of MDSCs. To investigate the effect of Bambuterol on GvL, the A20 lymphoma cell line was injected 4 hours before allo-HCT. Using two different doses of T cells (0.5 × 106 and 0.2 × 106) in B6 → BALB/c model, we found that Bambuterol preserved GvL by inducing CD44+ CD62L- NKG2D+ effector cells and CD44+ CD62L+ central memory cells. Since β2-AR agonists can affect cardiac function, we measured heart rate (HR) and blood pressure (BP) using a tail-cuff. There was no difference in BP and HR at day 21 and 28 after allo-HCT between mice receiving Bambuterol compared to mice receiving vehicle. In conclusion, these data reveal how β-AR signaling can influence donor T cell differentiation and function in murine GvHD models without decreasing GvL effect pointing to the feasibility of manipulation of β2-AR signaling to ameliorate clinical GvHD. Disclosures No relevant conflicts of interest to declare.

scholarly journals Deciphering the Plasmodium falciparum malaria-specific CD4+ T cell response: ex vivo detection of high frequencies of PD-1+TIGIT+ EXP1-specific CD4+ T cells using a novel HLA-DR11-restricted MHC class II tetramer

2021 ◽  
Author(s):  
Sophia Schulte ◽  
Janna Heide ◽  
Christin Ackermann ◽  
Sven Peine ◽  
Michael Ramharter ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cell Response ◽  
Cd4 T Cells ◽  
Ex Vivo ◽  
Class Ii ◽  
T Cell Response ◽  
Cd4 T Cell ◽  
Inhibitory Receptors

Abstract Relatively little is known about the ex vivo frequency and phenotype of the P. falciparum-specific CD4+ T cell response in humans. The exported protein 1 (EXP1) is expressed by plasmodia at both, the liver stage and blood stage, of infection making it a potential target for CD4+ and CD8+ effector T cells. Here, a fluorochrome-labelled HLA-DRB1*11:01-restriced MHC class II tetramer derived from the P. falciparum EXP1 (aa62-74) was established for ex vivo tetramer analysis and magnetic bead enrichment in ten patients with acute malaria. EXP1-specific CD4+ T cells were detectable in nine out of ten (90%) malaria patients expressing the HLA-DRB1*11 molecule with an average ex vivo frequency of 0.11% (0-0.22%) of total CD4+ T cells. The phenotype of EXP1-specific CD4+ T cells was further assessed using co-staining with activation (CD38, HLA-DR, CD26), differentiation (CD45RO, CCR7, KLRG1, CD127), senescence (CD57) and co-inhibitory (PD-1, TIGIT, LAG-3, TIM-3) markers as well as the ectonucleotidases CD39 and CD73. EXP1-specific tetramer+ CD4+ T cells had a distinct phenotype compared to bulk CD4+ T cells and displayed a highly activated effector memory phenotype with elevated levels of co-inhibitory receptors and activation markers: EXP1-specific CD4+ T cells universally expressed the co-inhibitory receptors PD-1 and TIGIT as well as the activation marker CD38 and showed elevated frequencies of CD39. These results demonstrate that MHC class II tetramer enrichment is a sensitive approach to investigate ex vivo antigen-specific CD4+ T cells in malaria patients that will aid further analysis of the role of CD4+ T cells during malaria.

Histone Deacetylase Inhibitors Induce Immuno-Dominant Suppression of Dendritic Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 456-456 ◽  
Author(s):  
Pavan Reddy ◽  
Yoshinobu Maeda ◽  
Raimon Duran-Struuck ◽  
Oleg Krijanovski ◽  
Charles Dinarello ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Hdac Inhibitors ◽  
Class Ii ◽  
Wild Type ◽  
Tnf Α

Abstract We and others have recently demonstrated that suberoylanilide hydroxamic acid (SAHA), a histone deacetylase (HDAC) inhibitor with anti-neoplastic properties, reduces experimental acute graft-versus-host disease (GVHD). We have now investigated the mechanisms of action of two HDAC inhibitors, SAHA and ITF 2357, on allogeneic immune responses. Bone marrow derived dendritic cells (DCs) were preincubated with the HDAC inhibitors at nanomolar concentrations for 16–18 hours and stimulated with lipopolysaccharide (LPS). Pretreatment of DCs caused a significant reduction in the secretion of TNF-α, IL-12p70 and IL-6 compared to the untreated controls (P< 0.005). Similar effects were seen using human peripheral blood mononuclear cell derived DCs. Pre-treatment of both murine and human DCs also significantly reduced their in vitro stimulation of allogeneic T cells as measured by proliferation and IFN-γ production (P<0.01). We determined the in vivo relevance of these observations utilizing a mouse model where the responses of allogeneic donor bm12 T cells depended on the function of injected host B6 DCs would stimulate. Recipient Class-II −/− B6 (H-2b) received 11 Gy on day -1 and were injected with 4–5 x 106 wild type B6 DCs treated with SAHA or with media on days -1 and 0 and then transplanted with 2 x 106 T cells and 5 x 106 TCDBM cells from either syngeneic B6 or allogeneic bm12 donors. SAHA treatment of DCs significantly reduced expansion of allogeneic donor CD4+ T cells on day +7 after BMT compared to controls (P<0.05). SAHA treatment induced a similarly significant reduction in the expansion of CD8+ cells in Class I disparate [bm1→β2M−/−] model. In vitro, SAHA treatment significantly suppressed the expression of CD40 and CD80 but did not alter MHC class II expression. Surprisingly, when mixed with normal DCs at 1:1 ratio, SAHA treated DCs dominantly suppressed allogeneic T cell responses. The regulation of T cell proliferation was not reversible by addition of IL-12, TNF-α, IL-18, anti-IL-10 or anti-TGFβ, either alone or in combination. Suppression of allogeneic responses was contact dependent in trans-well experiments. To address whether the regulation of SAHA treated DCs required contact with T cells, we devised a three cell experiment where SAHA treated DCs lacked the capacity to present antigens to T cells. DCs from B6 MHC Class II deficient (H-2b) were treated with SAHA and co-cultured with wild type B6 (H-2b) DCs along with purified allogeneic BALB/c (H-2d) CD4+ T cells in an MLR. Allogeneic CD4+ T cells proliferated well, demonstrating the regulation to be dependent on contact between SAHA treated DCs and T cells. To address the in vivo relevance of this suppression, we utilized a well characterized [BALB/c →B6] mouse model of acute GVHD. Recipient B6 animals received 11Gy on day -1 and were injected with of 5 million host type SAHA treated or control DCs on days −1, 0, and +2. Mice were transplanted on day 0 with 2 x 106 T cells and 5 x 106 BM from either syngeneic B6 or allogeneic BALB/c donors. Injection of SAHA treated DCs resulted in significantly better survival (60% vs. 10%, P < 0.01) and significantly reduced serum levels of TNF-α, donor T cell expansion and histopathology of GVHD on day +7 after BMT compared to the controls. We conclue that HDAC inhibitors are novel immunomodulators that regulate DC function and might represent a novel strategy to prevent GVHD.

Treatment of Established B16 Murine Melanoma Tumors with Tyrp-1 Specific CD4+ Lymphocytes.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3688-3688
Author(s):  
Pawel Muranski ◽  
Andrea Boni ◽  
Crystal M. Paulos ◽  
Kari R. Irvine ◽  
Paul A. Antony ◽  
...  
Keyword(s):  
T Cells ◽  
Immune System ◽  
T Cell ◽  
Solid Tumors ◽  
Mhc Class Ii ◽  
Cd4 T Cells ◽  
Tumor Response ◽  
Class Ii ◽  
B16 Melanoma ◽  
Cd4 Cells

Abstract T-cell mediated response against solid tumors has been mostly associated with CD8+ cytotoxic lymphocytes, which act directly on the MHC class I expressing tumors. In the previously published model, gp-100 melanoma antigen-specific pmel-1 CD8+ T cells required co-administration of IL-2 and vaccine to induce significant regression of poorly immunogenic B16 melanoma in mice. MHC class II restricted CD4+ T-cells (T helpers) may have multiple direct and indirect effects on the immune response, but their role in adoptive cell transfer (ACT) therapy of solid tumors remains mainly undefined and based on highly manipulated models involving foreign antigens. In order to investigate the function of tumor specific CD4+ T-cells we have generated a transgenic mouse expressing a TRP-1 T cell receptor (TCR) directed against class II restricted murine melanocyte differentiation antigen tyrp-1. In vitro expanded TRP1 CD4+ cells secreted Th1-like cytokines upon antigen stimulation and caused direct cytotoxic effect against B16 melanoma. In vivo they mediated a highly effective response against large (>1cm2) B16 melanoma tumors after ACT of as few as 2.5×105 cells/mouse into C57B6 animals, which was associated with a massive tumor infiltration with CD11b+, MAC3+, GR1+ cells. TRP-1 T cells caused partial tumor rejection and prolonged survival in MHC class II−/− hosts implying the ability to directly recognize low level MHC class II on the tumor. This suboptimal effect was significantly enhanced after co-transfer of MHC class II+ APCs into MHC class II−/− hosts allowing for antigen cross- presentation. Interestingly, Rag1−/− hosts, deficient in all T and B lymphocytes, demonstrated excellent initial response to treatment, but were not cured and succumbed to late relapse of the melanoma. Long-term responses were even more impaired in Rag1−/− γc−/− hosts, while complete and durable cure was observed in TCRα−/−, CD4−/− and C57B6 mice, suggesting involvement of other arms of the adaptive immune system. Similarly, co-transfer of 0.1×106 CD4+ TRP-1 cells and 1×106 CD8+ pmel-1 cells resulted in effective tumor regression, while the same numbers of each cells transferred individually were not sufficient to initiate a rejection. Introduction of tumor-specific CD4+ cells therefore eliminates the previously sine qua non need for co-administration of vaccine and IL-2 for effective treatment with CD8+ pmel-1 cells. Overall, we show that antigen-specific CD4+ T cells are highly effective in mediating the anti-tumor response by causing both the direct anti-tumor effect and by activating innate and adaptive arms of the immune system. These findings suggest that CD4+ T helper cells may play a key role in improving efficacy of ACT immunotherapy as central activators of the anti-tumor response.

Sign in / Sign up

Export Citation Format

Share Document