scholarly journals LAG3 Inhibition Decreases AML-Induced Immunosuppression and Improves T Cell-Mediated Killing

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3605-3605 ◽  
Author(s):  
Haitham Abdelhakim ◽  
Luis M. Cortez ◽  
Meizhang Li ◽  
Mitchell Braun ◽  
Barry S. Skikne ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cd8 T Cells ◽  
Healthy Donor ◽  
Mononuclear Cells ◽  
Culture Media ◽  
Hematologic Malignancy ◽  
Mhc I ◽  
Cd8 Cells

Background: Acute Myeloid Leukemia (AML) is an aggressive hematologic malignancy with known immune dyregulation. In addition to their capacity to rapidly divide, AML cells directly inhibit the activation and proliferation of immune cells in culture. Immunosuppressive features observed in the bone marrow of AML patients include upregulation of Tregs and production of immunosuppressive cytokines (e.g., TGFβ). Irradiating AML cells diminishes their immunosuppressive capacity while maintaining antigen presentation, leading to increased activation of T cells in co-culture. We subsequently identified the immune checkpoint LAG3 as an important mediator of AML-induced immunosuppression and LAG3 modulation as potential treatment strategy. Methods: Normal PBMC were isolated from healthy donors. PBMC were co-cultured with non-irradiated and irradiated (40 Gy) human AML cell lines (Kasumi1 (K1), THP1) separately at a 1:2 ratio. On day 3 of co-culture, immunophenotypic characterization of T cells was performed on a flow cytometer using the following surface markers: CD3, CD4, CD8, CD25, CD137, CD154, PD-1, TIM3, TIGIT, and LAG3 and intracellular IFNg and FOXP3. Supernatant from co-culture media were analyzed for cytokine (IL-2, IL-6, IL-10 & TGFβ) secretion by ELISA. CFSE-labeled AML cells were incubated with healthy donor PBMCs in the presence or absence of LAG3, then viability was measured by 7-ADD on flow cytometry. PBMCs were also isolated from AML patients' peripheral blood and mononuclear cells were isolated from their respective bone marrow samples. Primary AML cultures were established in RPMI complete media with 20% FBS. CFSE-7-ADD killing assay was conducted after incubation of AML cells with autologous PBMCs. Results: Healthy donor PBMC co-cultured with irradiated K1 AML cells showed higher intracellular IFNg expression (11.8% ± 3.1 v. 7% ± 3.3; n=7, P=0.012) and higher CD137 expression (9.3% ± 1.21 v. 5.7% ± 3.4; n=7, P<0.001) on CD8+ T cells, and higher CD154 expression on CD4+ cells (44.7% ± 20.3 v. 26.3% ± 14.2; n=5, P=0.002) when compared to the non-irradiated K1-PBMC co-cultures. There were fewer Tregs (CD4+ CD25+ FOXP3+) in the PBMC co-cultured with irradiated K1 cells (1.96% ± 0.37 v. 3.39% ± 0.58; n=4, P=0.03) compared to the non-irradiated K1-PBMC co-cultures. LAG3 expression on CD8+ T cells co-cultured with irradiated K1 was decreased (11.8% ± 2.4 v. 17.5% ± 2.5; n=4, P=0.002) compared to the PBMC co-cultured with non-irradiated K1 cells. No other changes in checkpoint expression on CD8+ T cells were observed. No changes were observed in MHCI or PDL1 expression on non-irradiated K1 AML cells before or after co-culture with PBMC. We observed similar findings with healthy donor PBMC co-cultured with a different AML cell line, THP1; CD137 expression was higher on CD8+ T cells (17.6% v. 6.5%; P=0.02, n=3). ELISA of the supernatant of culture media showed higher mean OD for secreted TGFβ in the non-irradiated AML co-cultures compared to the irradiated AML co-cultures at 6 hours (2.5 v. 2.0, P=0.03, n=3) and 72 hours (7.9 v. 5.3, P=0.04, n=3). Adding anti-LAG3 antibody (3DS223H; 100 µg/ml) to PBMC co-cultured with non-irradiated AML cells resulted in higher IFNg (16.3% v. 6.6%, P=0.01, n=4) and CD137 expression (6.5% v. 4.1%, p=.007, n=4) on CD8+ cells and fewer Tregs (1.7% v. 3.8%, P=.04, n=4) compared to no antibody added. Healthy donor PBMC (n=3) were incubated with CFSE labeled AML cells (K1 and THP1) separately at an effector:target ratio of 5:1. The addition of anti-LAG3 antibody lead to increased killing of both K1 and THP1 AML cells at 4 and 24 hours (Figure 1A). To eliminate the HLA mismatch effect, we incubated PBMC from AML patients with autologous AML cells in the presence or absence of anti-LAG3 (Figure 1B). MHC-I blocking (W6/32, 30 µg/ml) lead to inhibition of cell mediated killing in the presence of anti-LAG3 (Figure 1B). Conclusion: In this in vitro model, AML cells showed immunosuppressive features with decreased activation of CD8+ T cells, upregulation of Tregs, increased secretion of TGFβ and higher expression of LAG3 on CD8+ T cells. Antibody blocking of LAG3 mitigated this effect, resulting in increased activation of T cells, fewer T regs and improved MHC-I-mediated killing against AML cells. These results demonstrate that the immunosuppressive effects of AML cells can be modulated through inhibition of LAG-3, suggesting a potential strategy for future combination therapy in AML. Disclosures Lin: Jazz Pharmaceuticals: Honoraria; Pfizer: Membership on an entity's Board of Directors or advisory committees.

CD8+ but Not CD4+ T Cells Require Cognate Interactions with Target Tissues To Mediate GVHD across Only Minor H Antigens but CD4+ and CD8+ T Cells Both Require Direct Leukemic Contact for GVL.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 580-580 ◽  
Author(s):  
Warren D. Shlomchik ◽  
Catherine Matte ◽  
Jinli Liu ◽  
Dhanpat Jain ◽  
Jennifer McNiff
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Severe Disease ◽  
Target Tissue ◽  
Cd4 Cells ◽  
Mhc I ◽  
Cd8 Cells ◽  
Mhcii Expression

Abstract There has been debate as to whether CD4+ or CD8+ T cells require direct cognate interactions with their tissue targets to mediate GVHD. In one report, GVHD mediated by CD4 or CD8 cells did not require target tissue MHCI or MHCII expression in MHC-disparate models (Teshima, et al 2002). However, GVHD lethality may have been due to cytokines produced by high-frequency alloreactive T cells primed by MHC-disparate host APCs. In contrast, MHC-matched, multiple minor H antigen (miHA) disparate GVHD mediated by CD4 or CD8 cells has been reported to be reduced or absent in host → donor chimeric recipients of a second transplant with donor BM and T cells. In this case, host antigen was restricted to hematopoietic cells and the authors concluded that tissue miHA expression must be required (Korngold and Sprent, 1982; Jones et al, 2003). However these experiments did not address whether T cells directly interacted with MHC on target tissues. Rather they demonstrated that a continuing source of host antigen was essential. To resolve this we created bone marrow chimeras in which hematopoiesis was wild type (wt) while the parenchyma was either MHC I- (B6→B6 beta-2-microglobulin−/− (β2M−/−)) or MHC II− (B6→B6 IAb−/−) and used these chimeras as recipients in GVHD-inducing second transplants. We found that B6→B6β2M−/− chimeras were completely resistant clinically and pathologically to CD8-mediated GVHD induced by a second transplant with C3H.SW (H-2b) BM and CD8+ T cells whereas control B6→B6 chimeras developed severe disease. Thus, CD8 cells require direct cognate interactions with target host tissues to induce MHC-matched, miHA disparate GVHD. In contrast, B6→B6 IAb−/− chimeras developed similar clinical and histologic GVHD (liver, ear, skin and bowel) as did control B6→B6 chimeras when retransplanted with 129/J (H-2b) bone marrow and purified CD4+ T cells. Notably we observed lymphocytic infiltrates in involved organs. Therefore, CD4 cells can mediate tissue damage without directly recognizing alloantigen presented by MHCII on target epithelial cells. This suggests an indirect mechanism, perhaps mediated by T cell release of factors after stimulation in tissues by donor-derived APCs presenting host antigens. Alternatively, donor CD4 cells may activate miHA-bearing macrophages to release inflammatory mediators. To investigate the requirement for cognate recognition in GVL, we created murine CML via retroviral-mediated bcr-abl (p210) transduction of bone marrow from wt B6, B6 IAb−/− and B6 β2M−/− mice. Using the C3H.SW→B6 and 129→B6 GVHD models we found that both CD8-and CD4-mediated GVL requires leukemic expression of MHCI and MHCII, respectively. Thus both CD8-mediated GVHD and GVL required cognate T cell:target interactions. However, for CD4 cells only GVL, but not GVHD required target cell MHCII expression. This indicates that CD4-mediated GVL and GVHD have distinct mechanisms of action. Further understanding of these may provide insight in how to deliver GVL with less GVHD.

Lack of the CD8+ cell anti-HIV factor in CD8+ cell granules

Blood ◽  
2003 ◽  
Vol 102 (1) ◽  
pp. 180-183 ◽  
Author(s):  
Carl E. Mackewicz ◽  
Baikun Wang ◽  
Sunil Metkar ◽  
Matthew Richey ◽  
Christopher J. Froelich ◽  
...  
Keyword(s):  
T Cells ◽  
Antiviral Activity ◽  
Cd8 T Cells ◽  
Culture Media ◽  
Cd4 Cells ◽  
Antiviral Protein ◽  
Cd8 Cells ◽  
Cd8 Cell ◽  
Anti Hiv ◽  
Primary Granule

Abstract In HIV infection, CD8+ cells show cytotoxic and noncytotoxic anti-HIV activity. The latter function is mediated, at least in part, by a secreted antiviral protein, the CD8+ cell antiviral factor (CAF). Because antiviral effector molecules, such as perforin and granzymes, reside in the exocytic granules of CD8+ T cells, we examined the possibility that granules contain CAF-like activity. CD8+ cells from HIV-infected individuals showing strong CAF-mediated antiviral activity were induced to release their granule constituents into culture media. Within 1 hour of stimulation, high levels of granzyme B (a primary granule constituent) were found in the culture fluids of previously activated CD8+ cells. The same culture fluids contained no or very low amounts of CAF activity, as measured with HIV-infected CD4+ cells. Maximal levels of CAF activity were not observed until 5 or 7 days after stimulation, consistent with typical CAF production kinetics. In addition, extracts of granules purified from antiviral CD8+ cells did not show any CAF activity, whereas the cytoplasmic fraction of these cells showed substantial levels of antiviral activity. These findings suggest that CAF does not reside at appreciable levels in the exocytic granules of antiviral CD8+ T cells. (Blood. 2003;102: 180-183)

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 In vitro regulation of immunoglobulin synthesis after human marrow transplantation. II. Deficient T and non-T lymphocyte function within 3- 4 months of allogeneic, syngeneic, or autologous marrow grafting for hematologic malignancy

Blood ◽  
1982 ◽  
Vol 59 (4) ◽  
pp. 844-850 ◽  
Author(s):  
RP Witherspoon ◽  
LG Lum ◽  
R Storb ◽  
ED Thomas
Keyword(s):  
T Cells ◽  
T Lymphocytes ◽  
Mononuclear Cells ◽  
Hematologic Malignancy ◽  
Plaque Assay ◽  
Pokeweed Mitogen ◽  
Lymphocyte Function ◽  
Peripheral Blood Mononuclear ◽  
Immunoglobulin Secretion

Abstract Immunoglobulin secretion was studied in 37 patients between 19 and 106 days after allogeneic HLA-identical (30 patients), allogeneic one HLA- haplotype-identical (three patients), syngeneic (three patients), or autologous (one patient) marrow grafting. E rosette-positive (T) and E rosette-negative (non-T) peripheral blood mononuclear cells were cocultured with pokeweed mitogen for 6 days. Polyvalent immunoglobulin secretion was determined by counting plaque forming cells in a reverse hemolytic plaque assay. The number of antibody secreting cells in cocultures of autologous T and non-T lymphocytes was low in 40 of 44 tests conducted on samples from the 37 patients. Mononuclear or non-T cells from 38 of 40 tests failed to produce antibody when cultured with normal helper T cells. T cells from 23 of 37 tests failed to help normal non-T cells secrete antibody. T lymphocytes from 23 of 41 tests suppressed antibody production greater than 80% by normal T and non-T cells. The suppressor cells were radiosensitive in 17 of the 25 tests. The abnormal function of lymphocyte subpopulations in patients during the first 3 mo after syngeneic, allogeneic or autologous marrow grafting was similar regardless of the type of graft or the presence of acute graft versus host disease.

Prolonged Thrombocytopenia After Allogeneic Hematopoietic Stem Cell Transplantation (allo-HSCT) and Its Association with an Increase in CD8+ CX3CR1+ Cells in Bone Marrow.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3077-3077
Author(s):  
Xiao-hui Zhang ◽  
Guo-xiang Wang ◽  
Yan-rong Liu ◽  
Lan-Ping Xu ◽  
Kai-Yan Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Surface Expression ◽  
T Cell Subsets ◽  
Control Group ◽  
Hematopoietic Stem ◽  
Cell Counts

Abstract Abstract 3077 Background: Since prolonged thrombocytopenia (PT) is an independent risk factor for poor clinical outcome after allogeneic hematopoietic stem cell transplantation (allo-HSCT), the underlying mechanisms need to be understood in order to develop selective treatments. Previous studies1–4 have suggested that abnormalities in B cells may play a role in the pathogenesis of PT. However, abnormalities in B cells alone do not fully explain the complete pathogenic mechanisms of PT. Our previous studies5 showed that the frequency of megakaryocytes with a ploidy value ≤ 8N was significantly increased in patients who developed PT after allo-HSCT compared to the control group. Mechanisms concerning the megakaryocyte hypoplasia in PT after allo-HSCT are not well understood. Design and Methods: PT was defined as a platelet count ≤80 × 109/L for more than 3 months after HSCT, recovery of all other cell counts, and no apparent cause for thrombocytopenia, such as aGVHD, disease recurrence, CMV infection, or antiviral drug treatment at three months post-HSCT when all other blood cell counts had return to normal.5 We analyzed T cell subsets in bone marrow (BM) and peripheral blood (PB) from allo-HSCT recipients with and without PT (n = 23 and 17, respectively) and investigated the expression characteristics of homing receptors CX3CR1, CXCR4 and VLA-4 by flow cytometry. Futhermore, Mononuclear cells (MNCs) from PT patients and controls were cultured with and without autologous CD8+ T cells in vitro, and clarify the effect of activated CD8+ T cells on the ploidy and apoptosis of megakaryocytes in the bone marrow. Results: The results demonstrated that the percentage of CD3+ T cells in the BM was significantly higher in PT patients than the experimental controls (76.00 ± 13.04% and 57.49 ± 9.11%, respectively, P < 0.001), whereas this difference was not significant for the PB (71.01 ± 11.49% and 70.49 ± 12.89%, respectively, P = 0.911). While, some T cell subsets in the BM and PB from allo-HSCT recipients with PT were not significantly different from that of the experimental control group, such as CD8+ T cells, CD4+ T cells, CD4+ CD25bright T cells (regulatory T cells), CD44hi CD62Llo CD8+ T cells and naive T cells (CD11a+ CD45RA+). Furthermore, the surface expression of homing receptor CX3CR1 on BM T cells (64.16 ± 14.07% and 37.45 ± 19.66%, respectively, P < 0.001) and CD8+ T cells (56.25 ± 14.54% and 35.16 ± 20.81%, respectively, P = 0.036), but not in blood, were significantly increased in PT patients compared to controls. For these two groups of patients, the surface expression of CXCR4 and VLA-4 on T cells and CD8+ T cells from both BM and PB did not show significant differences. Through the study in vitro, we found that the activated CD8+ T cells in bone marrow of patients with PT might suppress apoptosis (MNC group and Co-culture group: 18.02 ± 3.60% and 13.39 ± 4.22%, P < 0.05, respectively) and Fas expression (MNC group and Co-culture group: 21.10 ± 3.93 and 15.10 ± 2.33, P <0.05, respectively) of megakaryocyte. In addition, megakaryocyte with a ploidy value ≤ 8N (MNC group: 40.03 ± 6.42% and 24.54 ± 4.31%, respectively, P < 0.05) was significantly increased in patients with PT compared to the control group. Conclusions: In conclusion, an increased surface expression of CX3CR1 on T cells may mediate the recruitment of CD8+ T cells into the bone marrow in patients with PT who received an allo-HSCT. Moreover, CD8+CX3CR1+ T cells, which can have significantly increased numbers in bone marrow of patients with PT, likely caused a reduction in the megakaryocyte ploidy, and suppressed megakaryocyte apoptosis via CD8+ T cell-mediated cytotoxic effect, possibly leading to impaired platelet production. Therefore, treatment targeting CX3CR1 should be considered as a reasonable therapeutic strategy for PT following allo-HSCT. Disclosures: No relevant conflicts of interest to declare.

Non–Host-Reactive Donor CD8+ T Cells of Tc2 Phenotype Potently Inhibit Marrow Graft Rejection

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4045-4050 ◽  
Author(s):  
Daniel H. Fowler ◽  
Bernard Whitfield ◽  
Michael Livingston ◽  
Paul Chrobak ◽  
Ronald E. Gress
Keyword(s):  
T Cells ◽  
Cd8 T Cells ◽  
Graft Rejection ◽  
Marrow Transplant ◽  
Type I ◽  
Marrow Graft ◽  
Murine Bone Marrow ◽  
Cd8 Cells ◽  
Preparative Regimen

Donor CD8+ T cells capable of host reactivity inhibit marrow graft rejection, but also generate graft-versus-host disease (GVHD). To evaluate whether the Tc1- and Tc2-type subsets of CD8 cells might inhibit rejection without host reactivity, we established an F1 into-parent murine bone marrow transplant model. Donor Tc1 and Tc2 cells were generated that preferentially secreted type I or type II cytokines; both subsets possessed potent cytolytic function, and clonally deleted host-type allospecific precursor CTL in vitro. B6 hosts receiving 950 cGy irradiation did not reject the donor marrow (F1 chimerism of 78.6%; n = 10), whereas hosts receiving 650 cGy rejected the donor marrow (3.8% chimerism; n = 8). At 650 cGy irradiation, the addition of Tc2 cells to the F1 marrow resulted in extensive F1 chimerism (70.8%) in 8 of 8 recipients; in contrast, alloengraftment was not consistently observed in mice receiving Tc1 cells or unmanipulated CD8 cells. Furthermore, when the preparative regimen was further reduced to 600 cGy, only hosts receiving the Tc2-type cells did not reject the F1 marrow. We conclude that Tc2 cells potently inhibit marrow graft rejection without inducing an alloaggressive response and that non–host-reactive Tc2 cells therefore facilitate engraftment across genetic barriers with reduced GVHD.

Sipuleucel-T (sip-T) induced lytic CD8+ T cell responses to target antigens in men with hormone-sensitive and castration-resistant prostate cancer (CRPC).

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 162-162
Author(s):  
Emmanuel S. Antonarakis ◽  
David I. Quinn ◽  
Adam S. Kibel ◽  
Daniel Peter Petrylak ◽  
Tuyen Vu ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
Cell Responses ◽  
Hormone Sensitive ◽  
Ctl Activity

162 Background: Sip-T is an FDA-approved immunotherapy for patients (pts) with asymptomatic or minimally symptomatic metastatic CRPC. Sip-T is manufactured from autologous peripheral blood mononuclear cells cultured with the immunogen PA2024, a fusion antigen of prostatic acid phosphatase (PAP) conjugated to granulocyte macrophage colony-stimulating factor. After sip-T, antibody and T cell responses to PA2024 and/or PAP correlate with improved survival. To further elucidate the mechanism of sip-T–induced immune responses, we evaluated the proliferative and lytic ability of PA2024- and PAP-specific CD8+ T cells. Methods: Mononuclear blood cells were labeled with the membrane dye carboxyfluorescein succinimidyl ester (CFSE) and cultured with PA2024 or PAP. In vitro proliferative and lytic CD8+ (cytotoxic T lymphocyte [CTL]) T cell responses to these antigens were evaluated by flow cytometry. For proliferation, progressive dilution of CFSE was measured. For CTL activity, the loss of intracellular granzyme B (GzB), indicating exocytosis of this apoptosis-mediating enzyme, was assessed. Samples were from 2 sip-T clinical trials STAND (NCT01431391) and STRIDE (NCT01981122), hormone-sensitive and CRPC pts, respectively. Results: Six wk after sip-T administration, CD8+ PAP- and PA2024-specific responses were observed (n=14 pts assessed). The magnitude of PA2024-specific CD8+ proliferative responses was greater than that for PAP-specific responses. CD8+ T cells from a subset of pts who exhibited PA2024- and/or PAP-specific proliferative responses were assessed for lytic ability. After in vitro antigen stimulation, CTL activity in all evaluated samples (n=14, PA2024; n=13, PAP) was demonstrated by a significant decrease (p<0.05) in intracellular GzB relative to a no-antigen control. Conclusions: Sip-T induced CD8+ CTL proliferation against the target antigens PAP and PA2024. Moreover, antigen-specific CTL activity provides the first direct evidence that sip-T can induce tumor cell lysis. These antigen-specific CD8+ lytic abilities were observed within 6 wk following sip-T, suggesting rapidly generated immune responses. Clinical trial information: NCT01431391; NCT01981122.

Differential effects of interferon-ß1b on cytokine patterns of CD4+ and CD8+ T cells derived from RRMS and PPMS patients

2011 ◽  
Vol 18 (5) ◽  
pp. 674-678 ◽  
Author(s):  
Sabine Skrzipek ◽  
Antje Vogelgesang ◽  
Barbara M Bröker ◽  
Alexander Dressel
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Progressive Multiple Sclerosis ◽  
Primary Progressive Multiple Sclerosis ◽  
Cytokine Release ◽  
Clinical Observations ◽  
Relapsing Remitting Multiple Sclerosis

The influence of interferon (IFN)-β on cytokine release by immune cells remains controversial. This study compared IFN-β1b effects on mononuclear cells, CD4+ and CD8+ T cells derived from healthy controls and relapsing–remitting multiple sclerosis (RRMS) and primary progressive multiple sclerosis (PPMS) patients. Effects of IFN-β1b (0-10,000 U/ml) on cytokine release were determined in cell culture. IFN-β1b inhibited IFN-γ and induced interleukin (IL)-4 selectively in RRMS-derived CD4+ T cells. IL-10 was significantly induced in all cell populations from RRMS but only marginally in PPMS. IL-5 was always inhibited; IL-17A remained unaltered. These in vitro data parallel clinical observations that IFN-β is most effective in RRMS.

Requirements for the promotion of allogeneic engraftment by anti-CD154 (anti-CD40L) monoclonal antibody under nonmyeloablative conditions

Blood ◽  
2001 ◽  
Vol 98 (2) ◽  
pp. 467-474 ◽  
Author(s):  
Patricia A. Taylor ◽  
Christopher J. Lees ◽  
Herman Waldmann ◽  
Randolph J. Noelle ◽  
Bruce R. Blazar
Keyword(s):  
Monoclonal Antibody ◽  
Bone Marrow ◽  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Immune Suppression ◽  
Regulatory T Cell ◽  
Cd4 Cells ◽  
Major Goal ◽  
Cd8 Cells

The promotion of alloengraftment in the absence of global immune suppression and multiorgan toxicity is a major goal of transplantation. It is demonstrated that the infusion of a single modest bone marrow dosage in 200 cGy-irradiated recipients treated with anti-CD154 (anti-CD40L) monoclonal antibody (mAb) resulted in chimerism levels of 48%. Reducing irradiation to 100 or 50 cGy permitted 24% and 10% chimerism, respectively. In contrast, pan–T-cell depletion resulted in only transient engraftment in 200 cGy-irradiated recipients. Host CD4+ cells were essential for alloengraftment as depletion of CD4+ cells abrogated engraftment in anti-CD154–treated recipients. Strikingly, the depletion of CD8+ cells did not further enhance engraftment in anti-CD154 mAb–treated recipients in a model in which rejection is mediated by both CD4+ and CD8+ T cells. However, anti-CD154 mAb did facilitate engraftment in a model in which only CD8+ T cells mediate rejection. Furthermore, CD154 deletional mice irradiated with 200 cGy irradiation were not tolerant of grafts, suggesting that engraftment promotion by anti-CD154 mAb may not simply be the result of CD154:CD40 blockade. Together, these data suggest that a CD4+regulatory T cell may be induced by anti-CD154 mAb. In contrast to anti-CD154 mAb, anti-B7 mAb did not promote donor engraftment. Additionally, the administration of either anti-CD28 mAb or anti-CD152 (anti–CTLA-4) mAb or the use of CD28 deletional recipients abrogated engraftment in anti-CD154 mAb–treated mice, suggesting that balanced CD28/CD152:B7 interactions are required for the engraftment-promoting capacity of anti-CD154 mAb. These data have important ramifications for the design of clinical nonmyeloablative regimens based on anti-CD154 mAb administration.

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