In Vivo T Cell Depletion Using Rabbit Derived ATG Leads to An Increased EBV-PTLD Risk Due to An Induced Imbalance Between B and T Cell Recovery Which Is Not Seen After Horse Derived ATG or Alemtuzumab

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1979-1979 ◽  
Author(s):  
C.J.M. Halkes ◽  
J.H.F. Falkenburg ◽  
H.M. van Egmond ◽  
J. Olde Wolbers ◽  
C.W.J. Starrenburg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd8 T Cells ◽  
Cell Depletion ◽  
Cell Recovery ◽  
Post Transplantation ◽  
T Cell Depletion

Abstract Abstract 1979 Control of replication of endogenous viruses like CMV and EBV is fully dependent on CMV or EBV specific T cells after allogeneic stem cell transplantation (alloSCT). In the absence of specific CD8 T cell control, proliferation of EBV infected B cells can lead to post transplantation lymphoproliferative disease (PTLD). In an initial cohort of patients treated with horse derived anti thymocyte globulin (h-ATG), no early PTLD was observed. However, due to unavailability in Europe, h-ATG had to be replaced by rabbit derived ATG (r-ATG), leading to an unacceptable high incidence of EBV-PTLD (26% during first 3 months after alloSCT). Replacement of r-ATG by alemtuzumab (ALT) significantly reduced the incidence of EBV-PTLD (3 months incidence of EBV-PTLD 2%). To determine the immunological basis of these findings we performed a detailed analysis of immune reconstitution in these three cohorts of transplanted patients. The first cohort (41 patients) received h-ATG (Lymphoglobulin) 10 mg/kg/day for 4 days. The second cohort (19 patients) received r-ATG (Thymoglobulin) 2.0 or 3.5 mg/kg/day for 4 days and the third cohort (60 patients) received ALT, 15 mg/day for 2 days. All grafts consisted of PBSC to which 20 mg of ALT was added for in vitro T cell depletion. All patients received a fludarabin and busulphan based conditioning regimen. No standard post transplantation immunosuppressive treatment was given. In the r-ATG cohort, early EBV-PTLD occurred after a median of 7 weeks (range 4–12 weeks) post alloSCT. Three r-ATG treated patients died while high levels of circulating EBV-DNA were present (> log 4.0 copies/mL). Incidence of CMV disease was not significantly different in the three cohorts (5%, 6% and 0%, respectively). In contrast to the other 2 cohorts, immune reconstitution in the r-ATG cohort was characterized by an imbalance between recovery of B cells and CD8 T cells. Already 3 weeks after alloSCT, the majority (67%) of r-ATG patients showed a more rapid reconstitution of B cells than CD8 T cells, leading to B cells outnumbering CD8 T cells. This was seen in only a small minority of patients after h-ATG and ALT (17% and 6%, respectively, p<0.01 versus r-ATG). Because rapid recovery of T cells in the alemtuzumab patients was frequently found in the presence of circulating ALT (mean concentration 0.43 μg/mL and 0.12 μg/mL after 3 and 6 weeks, respectively), the phenotype of circulating CD4 and CD8 T cells at 6 weeks after ALT was analyzed. The majority of circulating CD8 and CD4 T cells lacked CD52 expression (56% (range 0–99%) and 81% (range 0–93%), respectively). Using tetramer staining, cytotoxicity assays and analysis of cytokine production, we demonstrated the presence of functional CD52 negative as well as CD52 positive CMV and EBV specific CD8 T cells. Based on FLAER negativity, it was demonstrated that the CD52 negative T cells are GPI anchor deficient, representing a PNH-like clone escaping ALT induced cell lysis. Because almost half of the circulating CD8 T cells were CD52 positive, we examined expression of CD52 and the in-vitro sensitivity to ALT-mediated complement-dependent cell lysis (CDC) of B cells, CD4 and CD8 T cells of healthy donors. The highest CD52 expression was observed on B cells (mean fluorescence intensity (MFI) 120), resulting in 95% lysis after incubation with ALT and complement. Differential expression of CD52 was observed on CD4 and CD8 T cells, MFI 120 and 101 respectively, resulting in relative protection of CD52 positive CD8 compared to CD4 T cells against ALT-mediated CDC (52% and 90% lysis). We conclude that the high incidence of EBV-PTLD after in-vivo T cell depletion with r-ATG is caused by an induced imbalance between B and T cell recovery, which is not seen after h-ATG or ALT. In-vivo T cell depletion with ALT is associated with a relatively low risk of EBV disease because of efficient B cell depletion and persistent EBV immunity due to the relative insusceptibility for ALT of CD8 T cells and the development of functional CD52 negative escape variants of CD4 and CD8 T cells. Disclosures: Off Label Use: Alemtuzumab and Anti Thymocyte Globulin used for in vivo T cell depletion prior to allogeneic stem cell transplantation.

Low Incidence of Post-Transplant EBV-Related Disease After Alemtuzumab-Mediated T Cell Depletion Is Explained by the Differential Susceptibility to Alemtuzumab of B Cells and Protective CD8 and CD4 T Cells

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2330-2330
Author(s):  
Constantijn J.M. Halkes ◽  
Inge Jedema ◽  
Judith Olde Wolbers ◽  
Esther M van Egmond ◽  
Peter A. Von Dem Borne ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Cell Depletion ◽  
T Cell Depletion

Abstract Abstract 2330 In vivo T cell depletion with anti-thymocyte globulin (ATG) or alemtuzumab (anti-CD52) before reduced intensity allogeneic stem cell transplantation (alloSCT) in combination with in vitro T cell depletion with alemtuzumab reduces the risk of GVHD. Detectable levels of circulating antibodies are present up to several months after the alloSCT, leading to a delayed immune reconstitution which is associated with an increased incidence of opportunistic infections and early relapses. Prior to 2007, combined in vitro (Alemtuzumab 20 mg added “to the bag”) and in vivo T cell depletion with horse-derived ATG (h-ATG) resulted in good engraftment without GVHD in the absence of GVHD prophylaxis after reduced intensity alloSCT using conditioning with fludarabine and busulphan. Due to the unavailability of h-ATG, rabbit-derived ATG (r-ATG) 10–14 mg/kg was introduced in the conditioning regimen in 2007. Strikingly, in this cohort of patients, early EBV reactivation and EBV-associated post-transplantation lymphoproliferative disease (PTLD) was observed in 10 out of 18 patients at a median time of 6 weeks after alloSCT (range 5 to 11 weeks) in the absence of GVHD or immunosuppressive treatment. Analysis of T and B cell recovery early after transplantation revealed preferential depletion of T cells as compared to B cells, thereby allowing unrestricted proliferation of EBV infected B cells. Due to this unacceptable high incidence of EBV-related complications, in the conditioning regimen r-ATG was replaced by low dose alemtuzumab (15 mg i.v. day -4 and -3) in 2008. In this cohort of 60 patients, only 2 patients experienced transient EBV reactivation during the first 3 months after alloSCT and one patient developed an EBV-associated lymphoma 4 weeks after alloSCT. To investigate the mechanisms underlying the low incidence of EBV reactivation using alemtuzumab for T cell depletion, we studied the in vivo and in vitro effects of alemtuzumab on different lymphocyte subsets. First, lineage-specific reconstitution was studied in 20 patients from the alemtuzumab cohort with known CD52 negative diseases (11 AML and 9 multiple myeloma) to exclude the confounding effect of antibody absorption by malignant cells. Whereas at 3 weeks after alloSCT detectable numbers of circulating NK cells and T cells were observed (medians 71 (range 6–378), and 12 (range 1–1164)E6/L, respectively), no circulating B cells could be detected (median 0, range 0–1 E6/L). At 6 weeks after alloSCT, NK and T cell numbers further increased (medians 212 (52-813), and 130 (range 25–1509)E6/L, respectively), whereas B cell numbers still remained low in the majority of patients (median 15, range 0–813E6/L). In all patients, T cells were detectable before the appearance of circulating B cells. Furthermore, the expression of CD52 and the sensitivity to alemtuzumab-mediated complement-dependent cell lysis (CDC) of B cells, T cells and NK cells was measured in vitro. The highest CD52 expression was observed on B cells (mean fluorescence intensity (MFI) 120), resulting in 95% lysis after incubation with 10ug/mL alemtuzumab and rabbit complement. NK cells showed a significantly lower CD52 expression (MFI 41), which was also reflected by a lower susceptibility to alemtuzumab-mediated CDC (62% lysis). Interestingly, differential expression of CD52 was observed on CD4 and CD8 T cells (MFI 120 and 101, respectively). Cytotoxicity analysis revealed relative protection of CD8 compared to CD4 T cells against alemtuzumab-mediated CDC, resulting in 52% and 90% lysis, respectively. Based on these results, we investigated in detail the presence and phenotype of the CD4 and CD8 subsets and EBV-specific CD8 T cells using tetramer staining at 6 weeks after alloSCT. In accordance with the in-vitro expression and susceptibility data, circulating CD52+ CD8 T cells including EBV-specific T cells were detectable. Interestingly, the majority of circulating CD4 T cells (64-93%, n=4) lacked CD52 expression, explaining their capacity to persist in the presence of alemtuzumab. We conclude that in vivo and in vitro T cell depletion with alemtuzumab is associated with a relatively low risk of EBV-associated PTLD because of efficient B cell depletion and persistent EBV immunity allowed by the relative insusceptibility for alemtuzumab of CD8 T cells and the development of CD52 negative escape variants of CD4 T cells. Disclosures: No relevant conflicts of interest to declare.

Pentostatin Is Advantageous Relative to Fludarabine for in Vivo Murine T Cell Depletion, Suppression of T Cell Cytokine Secretion, and Inhibition of HVGR

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3483-3483
Author(s):  
Jacopo Mariotti ◽  
Jason Foley ◽  
Kaitlyn Ryan ◽  
Nicole Buxhoeveden ◽  
Daniel Fowler
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cytokine Secretion ◽  
Cell Depletion ◽  
T Cell Depletion ◽  
T Cell Suppression ◽  
Ifn Γ ◽  
Cell Suppression

Abstract Although fludarabine and pentostatin are variably utilized for conditioning prior to clinical allogeneic transplantation, limited data exists with respect to their relative efficacy in terms of host immune T cell depletion and T cell suppression. To directly compare these agents in vivo in a murine model, we compared a regimen of fludarabine plus cyclophosphamide (FC) similar to one that we previously developed (Petrus et al, BBMT, 2000) to a new regimen of pentostatin plus cyclophosphamide (PC). Cohorts of mice (n=5–10) received a three-day regimen consisting of P alone (1 mg/kg/d), F alone (100 mg/kg/d), C alone (50 mg/kg/d), or combination PC or FC. Similar to our previous data, administration of P, F, or C alone yielded minimal host T cell depletion (as measured by enumeration of splenic CD4+ and CD8+ T cells) and minimal T cell suppression (as determined by CD3, CD28 co-stimulation of a constant number of remaining splenic T cells and measuring resultant cytokine secretion by multi-analyte assay). The PC and FC regimens were similar in terms of myeloid suppression (p=.2). However, the PC regimen was more potent in terms of depleting host CD4+ T cells (remaining host CD4 number [× 10^6/spleen], 2.1±0.3 [PC] vs. 4.4±0.6 [FC], p<0.01) and CD8+ T cells (remaining host CD8 number, 1.7±0.2 [PC] vs. 2.4±0.5 [FC], p<0.01). Moreover, the PC regimen yielded greater T cell immune suppression than the FC regimen (cytokine values are pg/ml/0.5×10^6 cells/ml; all comparisons p<0.05) with respect to capacity to secrete IFN-γ (13±5 [PC] vs. 48±12 [FC]), IL-2 (59±44 [PC] vs. 258±32 [FC]), IL-4 (34±10 [PC] vs. 104±12 [FC]), and IL-10 (15±3 [PC] vs. 34±5 [FC]). In light of this differential in both immune T cell depletion and suppression of T cell effector function, we hypothesized that T cells from PC-treated recipients would have reduced capacity to mediate a host-versus-graft rejection response (HVGR) relative to FC-treated recipients. To directly test this hypothesis, we utilized a host T cell add-back model of rejection whereby BALB/c hosts were lethally irradiated (1050 cGy; day -2), reconstituted with host-type T cells from PC- or FC-treated recipients (day -1; 0.1 × 10^6 T cells transferred), and finally challenged with fully MHC-disparate transplantation (B6 donor bone marrow cells, 10 × 10^6 cells; day 0). In vivo HVGR was quantified by the following method at day 7 post-BMT: harvest of splenic T cells, stimulation with host- or donor-type dendritic cells, and use of six-color flow cytometry to detect host T cells, CD4 and CD8 subsets, and cytokine secretion by capture method. Consistent with our hypothesis, PC-treated cells acquired greatly reduced alloreactivity in vivo relative to FC-treated cells: the percentage of host CD4+ T cells secreting IFN-γ in an allospecific manner was 2.3±0.8% in recipients of PC-treated T cells and 62.7±13.4% in recipients of FC-treated cells (p<0.001). Similarly, the percentage of host CD8+ T cells secreting IFN-γ in an allospecific manner was 8.6±2.8% in recipients of PC-treated T cells and 92.7±4.1% in recipients of FC-treated T cells (p<0.001). We therefore conclude that at similar levels of myeloid suppression, the PC regimen is superior to the FC regimen in terms of murine T cell depletion, suppression of global T cell cytokine secretion, and inhibition of in vivo capacity to acquire allospecificity in response to fully genetically disparate marrow allografts. These data provide a rationale to develop PC regimens as an alternative to currently utilized FC regimens.

scholarly journals B Cells Directly Tolerize CD8+ T Cells

1998 ◽  
Vol 188 (11) ◽  
pp. 1977-1983 ◽  
Author(s):  
Sally R.M. Bennett ◽  
Francis R. Carbone ◽  
Tracey Toy ◽  
Jacques F.A.P. Miller ◽  
William R. Heath
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd8 T Cells ◽  
Cytotoxic T Lymphocyte ◽  
Tolerance Induction ◽  
Cell Receptor ◽  
I Cells

This report investigates the response of CD8+ T cells to antigens presented by B cells. When C57BL/6 mice were injected with syngeneic B cells coated with the Kb-restricted ovalbumin (OVA) determinant OVA257–264, OVA-specific cytotoxic T lymphocyte (CTL) tolerance was observed. To investigate the mechanism of tolerance induction, in vitro–activated CD8+ T cells from the Kb-restricted, OVA-specific T cell receptor transgenic line OT-I (OT-I cells) were cultured for 15 h with antigen-bearing B cells, and their survival was determined. Antigen recognition led to the killing of the B cells and, surprisingly, to the death of a large proportion of the OT-I CTLs. T cell death involved Fas (CD95), since OT-I cells deficient in CD95 molecules showed preferential survival after recognition of antigen on B cells. To investigate the tolerance mechanism in vivo, naive OT-I T cells were adoptively transferred into normal mice, and these mice were coinjected with antigen-bearing B cells. In this case, OT-I cells proliferated transiently and were then lost from the secondary lymphoid compartment. These data provide the first demonstration that B cells can directly tolerize CD8+ T cells, and suggest that this occurs via CD95-mediated, activation-induced deletion.

Regulatory and Activated T Cells in Stem Cell Autografts Collected by Mobilization with High-Dose Cyclophosphamide and Granulocyte Colony Stimulating Factor.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 5216-5216
Author(s):  
Maud Condomines ◽  
Philippe Quittet ◽  
Zhao-Yang Lu ◽  
Laure Nadal ◽  
Pascal Latry ◽  
...  
Keyword(s):  
Cell Cycle ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Function ◽  
Effector Memory ◽  
High Dose ◽  
Cell Recovery

Abstract High-dose chemotherapy (HDC) supported by autograft of hematopoietic progenitors (HP) is a standard therapy for patients with multiple myeloma (MM). High-dose cyclophosphamide (CTX) and G-CSF are widely used to collect HP. As the number of lymphocytes in the autograft is a powerful prognostic factor in patients with MM, our purpose was to study how CTX-G-CSF treatment affects the phenotype and function of T cells, in particular regulatory T cells (Treg), in 15 patients with MM. CTX induced severe T cell immunosuppression with a slow and partial T-cell recovery (a threefold decrease) at the time of HP collection. CTX-G-CSF treatment did not affect the percentages of central memory (CD45RA−, CCR7+), effector memory (CD45RA−, CCR7−), and late effector (CD45RA+, CCR7−) CD4 or CD8 T cells but a decrease of naïve CD4 cells (CD45RA+, CCR7+) was found. The percentages of CD25+ cells increased two- to threefold in CD4 or CD8 T cells, respectively. Post-CTX treatment CD4CD25+ cells included both activated CD4CD25low cells and CD4CD25high T cells. The latter were Treg because they expressed high level of FOXP3 and membrane CTLA-4 mRNA and protein and displayed functional suppressor function. In CTX-G-CSF leukaphereses from 15 patients with MM, the mean Treg number was one fifth that of CD34 and the CD3, CD4 and CD8 numbers respectively 3 fold, 2 fold and equal that of CD34. Post-CTX-G-CSF treatment CD3 cells did not cell cycle in vivo and died in short-term culture in vitro. Adding IL-2 or IL-15 induced their survival and cell cycle, and stimulation with anti-CD3 MoAb led to efficient growth in vitro. These results suggest that following CTX-G-CSF treatment, CD3 cells are preactivated in vivo and do not cell cycle, likely due to a lack of T cell growth factors in vivo. The current data indicate that CTX-G-CSF treatment profoundly affects T cell function without eliminating Treg. The persistence of Treg could be explained by an opposite effect of CTX known to kill Treg and of G-CSF amplifying Treg. Given the major impact of lymphocyte count on patients’ survival post HDC and HP and T cell graft, the present data invite to define novel therapeutic strategies to improve T cell recovery in vivo while limiting Treg expansion.

scholarly journals CD20 B Cell Depleting Therapy Is Associated with up-Regulation of CD8+CD25highFoxp3+ T Regulatory Cells in a Murine Model of Immune Thrombocytopenia (ITP)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2785-2785
Author(s):  
Li Guo ◽  
Rukhsana Aslam ◽  
Yajing Zhao ◽  
Edwin R. Speck ◽  
Heyu Ni ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd8 T Cells ◽  
Cd8 T Cell ◽  
Scid Mice ◽  
Cell Depletion ◽  
B Cell Depletion

Abstract Primary immune thrombocytopenia (ITP) is an autoimmune disease characterized by increased platelet destruction and/or impaired megakaryocyte production, mediated by autoreactive B cells and T cells. B cell depletion therapy by rituximab, a monoclonal human anti-CD20 antibody, has been shown effective in both anti-platelet antibody positive (B cell mediated) and negative (T cell mediated) ITP patients. Those patients responsive to rituximab therapy showed normalized CD4+ and CD8+ T cell responses (Stasi et al. Blood. 2007), however, the mechanism of T cell regulation by B cell depletion is not clear. One possibility is through normalization of CD4+ T helper cells or up-regulation of CD4+ regulatory T cells (Tregs) (Stasi et al. Blood. 2008). Another possibility is by suppression of activated conventional CD8+ T cells or the up-regulation of CD8+ Tregs. We examined the changes of both CD4+ and CD8+ T cells and Tregs (CD25highFoxp3+) after B cell depletion in vivo in our ITP mouse model. Briefly, BALB/c GPIIIa (CD61) KO mice were either given PBS (ND) or mouse monoclonal anti-CD20 antibody (B-dep, Biogen) at day -1 and day 13 (250ug/mouse, ip). Residual CD19+ B cells in peripheral blood were less than 0.1% within 24hours in the latter group. All mice were immunized by transfusions of wildtype (WT) platelets at day 0, 7, 14, and 21 (1×108/mouse, iv). At day 28, we examined the percentages of T cell subsets in the spleens of the immunized mice. B cell-depleted immune CD61 KO mice showed significantly higher percentages of both CD3+CD8+ T cells and CD8+CD25highFoxp3+ T cells (Table 1). There was no significant difference in the CD3+CD4+ and CD4+CD25highFoxp3+ T cell populations. Both ND and B-dep immune CD61 KO splenocytes showed increased cytotoxicity activity against CD61+ PU5-1.8 target cells in vitro compared with naïve CD61 KO splenocytes, indicating the activation of CD8+ T cells. To test their in vivo effect on ITP development, splenocytes were engrafted from immune mice into irradiated and AsialoGM-1 treated severe combined immunodeficient (SCID) mice at a dose of 2.5×104/mouse and the mice were monitored for weekly platelet counts. ND and in vitro B cell depleted splenocytes from immune KO mice induced persistent ITP during 3 weeks observation whereas splenocytes from B-dep immune mice did not. To further confirm the role of B cell depletion on CD8+ T cell responses, CD8+ T cells from either ND or B-dep immune CD61 KO splenocytes were purified and transferred into SCID mice at 3×104/mouse. CD4+ T cells from ND immune CD61 KO splenocytes were added at 3×104/mouse to all the SCID mice to support the CD8+ T cell survival in vivo. SCID mice received CD8+ T cells from B-dep group showed higher platelet count at Day 14. Overall, our results indicate a protective role of CD8+CD25highFoxp3+ T cells against the development of cell mediated ITP that is enhanced by B cell depleting therapy in vivo. Table 1. CD61 KO MouseSpleens CD3+CD8+(%) CD8+CD25highFoxp3+ (%) Naïve Control 9.12±0.37 0.12±0.08 Immune, ND 6.78±2.37 0.0925±0.03 Immune, B-dep 14.15±5.1 0.2367±0.11 P value (ND vs B-dep) 0.0007 0.0064 Disclosures No relevant conflicts of interest to declare.

scholarly journals CD28 Costimulation Is Required for In Vivo Induction of Peripheral Tolerance in CD8 T Cells

2002 ◽  
Vol 197 (1) ◽  
pp. 19-26 ◽  
Author(s):  
Melanie S. Vacchio ◽  
Richard J. Hodes
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Tolerance Induction ◽  
Peripheral Tolerance ◽  
Cd8 Cells ◽  
Costimulatory Signal ◽  
Cd28 Costimulation

Whereas ligation of CD28 is known to provide a critical costimulatory signal for activation of CD4 T cells, the requirement for CD28 as a costimulatory signal during activation of CD8 cells is less well defined. Even less is known about the involvement of CD28 signals during peripheral tolerance induction in CD8 T cells. In this study, comparison of T cell responses from CD28-deficient and CD28 wild-type H-Y–specific T cell receptor transgenic mice reveals that CD8 cells can proliferate, secrete cytokines, and generate cytotoxic T lymphocytes efficiently in the absence of CD28 costimulation in vitro. Surprisingly, using pregnancy as a model to study the H-Y–specific response of maternal T cells in the presence or absence of CD28 costimulation in vivo, it was found that peripheral tolerance does not occur in CD28KO pregnants in contrast to the partial clonal deletion and hyporesponsiveness of remaining T cells observed in CD28WT pregnants. These data demonstrate for the first time that CD28 is critical for tolerance induction of CD8 T cells, contrasting markedly with CD28 independence of in vitro activation, and suggest that the role of CD28/B7 interactions in peripheral tolerance of CD8 T cells may differ significantly from that of CD4 T cells.

scholarly journals DNAM-1 promotes activation of cytotoxic lymphocytes by nonprofessional antigen-presenting cells and tumors

2008 ◽  
Vol 205 (13) ◽  
pp. 2965-2973 ◽  
Author(s):  
Susan Gilfillan ◽  
Christopher J. Chan ◽  
Marina Cella ◽  
Nicole M. Haynes ◽  
Aaron S. Rapaport ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Adhesion Molecules ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Cd8 T Cell ◽  
Antigen Presenting

Natural killer (NK) cells and CD8 T cells require adhesion molecules for migration, activation, expansion, differentiation, and effector functions. DNAX accessory molecule 1 (DNAM-1), an adhesion molecule belonging to the immunoglobulin superfamily, promotes many of these functions in vitro. However, because NK cells and CD8 T cells express multiple adhesion molecules, it is unclear whether DNAM-1 has a unique function or is effectively redundant in vivo. To address this question, we generated mice lacking DNAM-1 and evaluated DNAM-1–deficient CD8 T cell and NK cell function in vitro and in vivo. Our results demonstrate that CD8 T cells require DNAM-1 for co-stimulation when recognizing antigen presented by nonprofessional antigen-presenting cells; in contrast, DNAM-1 is dispensable when dendritic cells present the antigen. Similarly, NK cells require DNAM-1 for the elimination of tumor cells that are comparatively resistant to NK cell–mediated cytotoxicity caused by the paucity of other NK cell–activating ligands. We conclude that DNAM-1 serves to extend the range of target cells that can activate CD8 T cell and NK cells and, hence, may be essential for immunosurveillance against tumors and/or viruses that evade recognition by other activating or accessory molecules.

scholarly journals P01.02 TLR-mediated suppression of the CCL22-CCR4 axis as a new target for tumor immunotherapy

2021 ◽  
Vol 9 (Suppl 1) ◽  
pp. A3.2-A4
Author(s):  
J Grün ◽  
I Piseddu ◽  
C Perleberg ◽  
N Röhrle ◽  
S Endres ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
B Cells ◽  
Regulatory T Cells ◽  
Type I ◽  
List Type ◽  
Gm Csf

BackgroundUnmethylated CpG-DNA is a potent ligand for the endosomal Toll-like-receptor-9, important for the immune activation to pathogen-associated molecules.1 CpG and other TLR-ligands show effective immunotherapeutic capacities in cancer treatment by inducing an antitumorigenic immunity.2 They are able to reduce tumor progression by reduction of intratumoral secretion of the immunoregulating chemokine CCL223 and subsequent recruitment of immunosuppressive regulatory T cells (Treg), which express CCR4 the only so far known receptor for CCL22.4 Our recent work has shown that CCL22 secretion by dendritic cells (DC) in the lymph node, mediates tolerance by inducing DC-Treg contacts.5 Indeed, in the absence of CCL22, immune responses to vaccination were stronger and resulted in tumor rejection.6 Therefore, we are aiming to investigate the effects of TLR-ligands on systemic CCL22 levels, elucidating all involved mechanisms to identify new targets for cancer immunotherapy.Materials and MethodsT, B and CD11c+ DCs of wildtype (wt) and RAG1-/- mice were isolated from splenocytes by magnetic-activated cell sorting for in vitro assays. Different co-cultures were incubated with CpG and GM-CSF, known as an CCL22 inducer.5 For in vivo experiments, wt mice were treated with CpG, R484 or poly(I:C) alone and in combination with GM-CSF. CCL22-levels in a number of organs were analyzed.ResultsAnalyzing the different immune cell compartments in vitro, we found that DCs in whole splenocytes secrete CCL22 during culture while DC cultured alone showed no CCL22 secretion. When treated with CpG, CCL22-levels were reduced in splenocytes, while it was induced in DC culture alone. The same results were seen when RAG splenocytes, that lack functional B and T cells, were cultured with CpG. CpG treated B cells were able to suppress CCL22 secretion by DC unlike T cells alone. Co-cultures of T and B cells treated with CpG, however, induced the strongest CCL22 suppression in DC. In vivo, we could show that all TLR ligands tested reduced CCL22 in a number of organs significantly. Furthermore, CpG showed the strongest suppression of CCL22 even in the presence of the CCL22 inducer GM-CSF.5ConclusionsWe could show that B cells with T cells mediate CCL22 suppression by TLR ligands. The fact that CpG was able to reduce CCL22 levels even in the presence of the inducer GM-CSF demonstrates the potent CCL22 suppressive capacity of TLR ligands.ReferencesO’Neill LA, et al. The history of toll-like receptors – redefining innate immunity. Nat Rev Immunol 2013;13(6):453–60.Rothenfusser S, et al. Recent advances in immunostimulatory CpG oligonucleotides. Curr Opin Mol Ther 2003;5(2):98–106.Wang S, et al. Intratumoral injection of a CpG oligonucleotide reverts resistance to PD-1 blockade by expanding multifunctional CD8+ T cells. Proc Natl Acad Sci U S A 2016;113(46): E7240–E7249.Rapp M, et al. CCL22 controls immunity by promoting regulatory T cell communication with dendritic cells in lymph nodes. J Exp Med 2019;216(5):1170–1181.Piseddu I, et al. Constitutive expression of CCL22 is mediated by T cell-derived GM-CSF. J Immunol 2020;205(8):2056–2065.Anz D, et al. Suppression of intratumoral CCL22 by type i interferon inhibits migration of regulatory T cells and blocks cancer progression. Cancer Res 2015;75(21):4483–93.Disclosure InformationJ. Grün: None. I. Piseddu: None. C. Perleberg: None. N. Röhrle: None. S. Endres: None. D. Anz: None.

scholarly journals 708 Novel ways to exploit IL-21 to augment adoptive T cell transfer therapy against tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A737-A737
Author(s):  
Anna Cole ◽  
Guillermo Rangel RIvera ◽  
Aubrey Smith ◽  
Megan Wyatt ◽  
Brandon Ware ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Cells ◽  
Striking Difference ◽  
T Cell Therapy ◽  
Cell Immunity ◽  
Emory University

BackgroundIL-21 enhances the anti-tumor capacity of adoptively transferred CD8+ T cells, while IL-2 and IL-15 impair T cell immunity by driving their expansion to a more differentiated status. Yet, these cytokines can act on many different immune cells. Given the potency of IL-21, we tested if this cytokine directly augments T cells or rather if it enhances other immune cells in the culture that indirectly improves T cell therapy.MethodsTo test this question, splenocytes from pmel-1 transgenic mice were used, as all CD8+ T cells express a transgenic TCR specific for tumor-antigen gp10025–33 overexpressed on melanoma. We then peptide activated naïve CD8+ T cells enriched or not from the spleen of pmel-1 mice and expanded them in the presence of IL-21 or IL-2 (10 ng/mL) for four days. Expanded pmel-1 from these various cultures were then restimulated with irradiated splenocytes pulsed with gp10025–33 and grown an additional seven days with IL-2 (10 ng/mL), irrespective of their initial cytokine condition. The in vitro memory phenotype, exhaustion profile, and cytokine secretion of these cultures were then assayed. Furthermore, mice bearing B16KVP melanoma tumors were infused with pmel-1 T cells expanded via these various approaches and compared for their relative capacity to engraft, persist, and regress tumor in vivo.ResultsInterestingly, we discovered that IL-21-treated T cells generated from bulk splenocytes are phenotypically and functionally distinct from IL-21-treated isolated T cells. Upon restimulation, IL-21-treated T cells from bulk splenocytes exhibited an exhausted phenotype that was like anergic IL-2-treated T cells. Moreover, few cells expressed CD62L but expressed heightened markers of suppression, including TIM3, PD-1, and EOMES. Moreover, they produced more effector molecules, including granzyme B and IFN-gamma. In vivo IL-21-treated T cells expanded from bulk splenocytes engrafted and persisted poorly, in turn mediating suboptimal regression of melanoma. Conversely, IL-21 dramatically bolstered the engraftment and antitumor activity of T cells only if they were first isolated from the spleen prior to their expansion and infusion into the animal.ConclusionsCollectively, our data shows that IL-21 may improve ACT therapy best when used directly on antitumor CD8+ T cells. Further studies will illuminate the mechanism behind this striking difference and determine whether other cell subsets reactive to IL-21 cause T cell dysfunction and/or reduced bioavailability. These findings are important for defining the best culture conditions in which to use IL-21 for ACT.AcknowledgementsWe would like to acknowledge Emory University, The Winship Cancer Institute, and the Pediatrics/Winship Flow Cytometry Core.Ethics ApprovalAll animal procedures were approved by the Institutional Animal Care and Use Committee of Emory University, protocol number 201900225.

scholarly journals Human bone marrow and peripheral blood T lymphocyte depletion: efficacy and effects of both T cells and monocytes on growth of hematopoietic progenitors

Blood ◽  
1985 ◽  
Vol 65 (3) ◽  
pp. 663-679
Author(s):  
L Levitt ◽  
TJ Kipps ◽  
EG Engleman ◽  
PL Greenberg
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocyte ◽  
Peripheral Blood ◽  
Cell Depletion ◽  
Target Cells ◽  
Facs Analysis ◽  
Hematopoietic Progenitors ◽  
T Cell Depletion

The efficacy of four separate methods of human bone marrow T lymphocyte depletion was assessed, and the effect of T cells and monocytes on in vitro growth of marrow (CFU-GEMM, BFU-E, and CFU-GM) and peripheral blood (BFU-E) hematopoietic progenitors was determined. Extent of T cell depletion was assessed by multiparameter fluorescent cell sorter (FACS) analysis and by functional studies. Cells staining positively by FACS analysis for one or more of three separate fluorescent pan-T cell monoclonal antibodies (MCAbs) comprised 8.4% to 9.5% of control marrow mononuclear cells (MNCs). T cells constituted 3.2% to 5.1% of marrow following single, sequential, or combination treatment with two different pan-T cell MCAbs (Leu 1 and TM1) plus complement, 1.5% to 2.2% of marrow following solid-phase immunoabsorption (“panning”), 0.2% of marrow after sheep cell rosetting, and only 0.05% of marrow after FACS selective cell sorting and gated separation. T cells made up 59% to 73% of control peripheral blood MNCs and 0.8% to 2.8% of peripheral MNCs following sheep cell rosetting plus treatment with Leu 1 MCAb and complement. Mitogen (PHA, Con A) and allogeneic MLC-induced blastogenic responses (stimulation indices, experimental/control or E/C) revealed a concordant decrement in marrow T cell function after MCAb plus complement (E/C of 3.9 to 9.0), after panning (E/C of 1.6 to 3.5) and after sheep cell rosetting (E/C of 0.7 to 1.3), compared with control marrow (E/C of 5.3 to 15.7). After T cell depletion, marrow BFU-E growth was 95% to 120% of control, CFU-GM growth was 90% to 108% of control, and CFU-GEMM growth was 89% to 111% of control. Marrow T cell and/or monocyte depletion did not alter erythropoietin-dependent BFU-E growth in the absence of Mo-conditioned medium (81% to 95% of control), and the addition of as many as 50 to 100 X 10(3) purified marrow monocytes or T cells to 10(5) autologous nonadherent T cell-depleted marrow target cells had a negligible (P greater than .1) effect on marrow BFU-E growth in vitro. Peripheral blood (PB) BFU-E/10(5) T- depleted target cells were 106% +/- 19% of expected; PB BFU-E growth was significantly diminished after monocyte depletion alone (7% +/- 6% of expected) or after monocyte plus T cell depletion (8% +/- 4% of expected).(ABSTRACT TRUNCATED AT 400 WORDS)

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