ABSTRACT
Myocardial infarction (MI) is irreversible damage to the myocardial tissue caused by prolonged ischemia/hypoxia, subsequently leading to loss of contractile function and myocardial damage. However, after a perilous period, ischemia-reperfusion (IR) itself causes the generation of oxygen free radicals, disturbance in cation homeostasis, depletion of cellular energy stores, and activation of innate and adaptive immune responses. The present study employed Abatacept (ABT), which is an anti-inflammatory drug, originally used as an antirheumatic response agent. To investigate the cardioprotective potential of ABT, primarily, the dose was optimized in a chemically induced model of myocardial necrosis. Thereafter, ABT optimized the dose of 5 mg/kg s.c. OD was investigated for its cardioprotective potential in a surgical model of myocardial IR injury, where animals (n = 30) were randomized into five groups: Sham, IR-C, Telmi10 + IR (Telmisartan, 10 mg/kg oral OD), ABT5 + IR, ABT perse. ABT and telmisartan were administered for 21 days. On the 21st day, animals were subjected to LAD coronary artery occlusion for 60 min, followed by reperfusion for 45 min. Further, the cardioprotective potential was assessed through hemodynamic parameters, oxidant-antioxidant biochemical enzymatic parameters, cardiac injury, inflammatory markers, histopathological analysis, TUNEL assay, and immunohistochemical evaluation, followed by immunoblotting to explore signaling pathways. The statistics were performed by one-way analysis of variance, followed by the Tukey comparison post hoc tests. Noteworthy, 21 days of ABT pretreatment amended the hemodynamic and ventricular functions in the rat models of MI. The cardioprotective potential of ABT is accompanied by inhibiting MAP kinase signaling and modulating Nrf-2/HO-1 proteins downstream signaling cascade. Overall, the present work bolsters the previously known anti-inflammatory role of ABT in MI and contributes a mechanistic insight and application of clinically approved drugs in averting the activation of inflammatory response.
Subject(s)
Abatacept , Disease Models, Animal , Inflammation , Myocardial Infarction , Animals , Rats , Myocardial Infarction/drug therapy , Myocardial Infarction/pathology , Male , Inflammation/drug therapy , Inflammation/pathology , Abatacept/pharmacology , Abatacept/therapeutic use , Rats, Wistar , Myocardial Reperfusion Injury/drug therapy , Myocardial Reperfusion Injury/pathologyABSTRACT
Immune checkpoint therapies (ICT) improve overall survival of patients with cancer but may cause immune-related adverse events (irAEs) such as myocarditis. Cytotoxic T lymphocyte-associated antigen 4 immunoglobulin fusion protein (CTLA-4 Ig), an inhibitor of T cell costimulation through CD28, reverses irAEs in animal models. However, concerns exist about potentially compromising antitumor response of ICT. In mouse tumor models, we administered CTLA-4 Ig 1) concomitantly with ICT or 2) after ICT completion. Concomitant treatment reduced antitumor efficacy, while post-ICT administration improved efficacy without affecting frequency and function of CD8 T cells. The improved response was independent of the ICT used, whether CTLA-4 or PD-1 blockade. The frequency of Tregs was significantly decreased with CTLA-4 Ig. The resulting increased CD8/Treg ratio potentially underlies the enhanced efficacy of ICT followed by CTLA-4 Ig. This paradoxical mechanism shows that a CTLA-4 Ig regimen shown to reduce irAE severity does not compromise antitumor efficacy.
Subject(s)
CTLA-4 Antigen , Immunotherapy , Animals , Mice , Immunotherapy/methods , CTLA-4 Antigen/antagonists & inhibitors , CTLA-4 Antigen/immunology , Immune Checkpoint Inhibitors/therapeutic use , Immune Checkpoint Inhibitors/pharmacology , CD8-Positive T-Lymphocytes/immunology , T-Lymphocytes, Regulatory/immunology , Cell Line, Tumor , Abatacept/therapeutic use , Abatacept/pharmacology , Female , Humans , Mice, Inbred C57BL , Neoplasms/immunology , Neoplasms/therapy , Neoplasms/drug therapy , Programmed Cell Death 1 Receptor/antagonists & inhibitors , Programmed Cell Death 1 Receptor/immunologyABSTRACT
The efficacy of costimulation blockade with CTLA4-Ig (belatacept) in transplantation is limited due to T cell-mediated rejection, which also persists after induction with anti-thymocyte globulin (ATG). Here, we investigate why ATG fails to prevent costimulation blockade-resistant rejection and how this barrier can be overcome. ATG did not prevent graft rejection in a murine heart transplant model of CTLA4-Ig therapy and induced a pro-inflammatory cytokine environment. While ATG improved the balance between regulatory T cells (Treg) and effector T cells in the spleen, it had no such effect within cardiac allografts. Neutralizing IL-6 alleviated graft inflammation, increased intragraft Treg frequencies, and enhanced intragraft IL-10 and Th2-cytokine expression. IL-6 blockade together with ATG allowed CTLA4-Ig therapy to achieve long-term, rejection-free heart allograft survival. This beneficial effect was abolished upon Treg depletion. Combining ATG with IL-6 blockade prevents costimulation blockade-resistant rejection, thereby eliminating a major impediment to clinical use of costimulation blockers in transplantation.
Subject(s)
Abatacept , Antilymphocyte Serum , Graft Rejection , Graft Survival , Heart Transplantation , Interleukin-6 , T-Lymphocytes, Regulatory , Animals , Male , Mice , Abatacept/pharmacology , Abatacept/therapeutic use , Allografts/immunology , Antilymphocyte Serum/pharmacology , Antilymphocyte Serum/therapeutic use , Graft Rejection/immunology , Graft Rejection/prevention & control , Graft Survival/drug effects , Graft Survival/immunology , Heart Transplantation/adverse effects , Immunosuppressive Agents/pharmacology , Interleukin-10/metabolism , Interleukin-10/immunology , Interleukin-6/metabolism , Lymphocyte Depletion , Mice, Inbred BALB C , Mice, Inbred C57BL , T-Lymphocytes, Regulatory/immunology , T-Lymphocytes, Regulatory/drug effectsABSTRACT
Exhausted CD8 T cells (TEX) are associated with worse outcome in cancer yet better outcome in autoimmunity. Building on our past findings of increased TIGIT+KLRG1+ TEX with teplizumab therapy in type 1 diabetes (T1D), in the absence of treatment we found that the frequency of TIGIT+KLRG1+ TEX is stable within an individual but differs across individuals in both T1D and healthy control (HC) cohorts. This TIGIT+KLRG1+ CD8 TEX population shares an exhaustion-associated EOMES gene signature in HC, T1D, rheumatoid arthritis (RA), and cancer subjects, expresses multiple inhibitory receptors, and is hyporesponsive in vitro, together suggesting co-expression of TIGIT and KLRG1 may broadly define human peripheral exhausted cells. In HC and RA subjects, lower levels of EOMES transcriptional modules and frequency of TIGIT+KLRG1+ TEX were associated with RA HLA risk alleles (DR0401, 0404, 0405, 0408, 1001) even when considering disease status and cytomegalovirus (CMV) seropositivity. Moreover, the frequency of TIGIT+KLRG1+ TEX was significantly increased in RA HLA risk but not non-risk subjects treated with abatacept (CTLA4Ig). The DR4 association and selective modulation with abatacept suggests that therapeutic modulation of TEX may be more effective in DR4 subjects and TEX may be indirectly influenced by cellular interactions that are blocked by abatacept.
Subject(s)
Abatacept , Alleles , Arthritis, Rheumatoid , CD8-Positive T-Lymphocytes , Receptors, Immunologic , Humans , Abatacept/therapeutic use , Abatacept/pharmacology , Receptors, Immunologic/genetics , Receptors, Immunologic/metabolism , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/immunology , Arthritis, Rheumatoid/genetics , Male , Female , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/drug effects , Adult , Lectins, C-Type/genetics , Lectins, C-Type/metabolism , HLA Antigens/genetics , HLA Antigens/immunology , Middle Aged , Antirheumatic Agents/therapeutic use , Genetic Predisposition to Disease , T-Cell ExhaustionABSTRACT
Calcineurin inhibitors (CNIs) are critical in preventing rejection posttransplantation but pose an increased risk of post-transplant diabetes (PTD). Recent studies show that late conversion from CNIs to belatacept, a costimulation blocker, improves HbA1c in kidney transplant recipients with PTD or de novo diabetes. This study investigates whether the observed effects on PTD stem solely from CNI withdrawal or if belatacept influences PTD independently. The study assessed the impact of tacrolimus and belatacept on insulin secretion in MIN6 cells (a beta cell line) and rat islets. Tacrolimus and belatacept were administered to the cells and islets, followed by assessments of cell viability and insulin secretion. Tacrolimus impaired insulin secretion without affecting cell viability, while belatacept showed no detrimental effects on either parameter. These findings support clinical observations of improved HbA1c upon switching from tacrolimus to belatacept. Belatacept holds promise in islet or pancreas transplantation, particularly in patients with unstable diabetes. Successful cases of islet transplantation treated with belatacept without severe hypoglycemia highlight its potential in managing PTD. Further research is needed to fully understand the metabolic changes accompanying the transition from CNIs to belatacept. Preserving insulin secretion emerges as a promising avenue for investigation in this context.
Subject(s)
Abatacept , Immunosuppressive Agents , Insulin , Tacrolimus , Tacrolimus/therapeutic use , Tacrolimus/pharmacology , Abatacept/therapeutic use , Abatacept/pharmacology , Animals , Rats , Insulin/metabolism , Immunosuppressive Agents/therapeutic use , Immunosuppressive Agents/pharmacology , Humans , Male , Insulin Secretion/drug effects , Mice , Islets of Langerhans Transplantation/methods , Cell Line , Cell Survival/drug effects , Diabetes Mellitus/drug therapy , Diabetes Mellitus/metabolism , Islets of Langerhans/drug effects , Islets of Langerhans/metabolismABSTRACT
ABSTRACT: Prepubertal obesity is growing at an alarming rate and is now considered a risk factor for renal injury. Recently, we reported that the early development of renal injury in obese Dahl salt-sensitive (SS) leptin receptor mutant (SS LepR mutant) rats was associated with increased T-cell infiltration and activation before puberty. Therefore, the current study investigated the effect of inhibiting T-cell activation with abatacept on the progression of renal injury in young obese SS LepR mutant rats before puberty. Four-week-old SS and SS LepR mutant rats were treated with IgG or abatacept (1 mg/kg; ip, every other day) for 4 weeks. Abatacept reduced the renal infiltration of T cells by almost 50% in SS LepR mutant rats. Treatment with abatacept decreased the renal expression of macrophage inflammatory protein-3 alpha while increasing IL-4 in SS LepR mutant rats without affecting SS rats. While not having an impact on blood glucose levels, abatacept reduced hyperinsulinemia and plasma triglycerides in SS LepR mutant rats without affecting SS rats. We did not observe any differences in the mean arterial pressure among the groups. Proteinuria was markedly higher in SS LepR mutant rats than in SS rats throughout the study, and treatment with abatacept decreased proteinuria by about 40% in SS LepR mutant rats without affecting SS rats. We observed significant increases in glomerular and tubular injury and renal fibrosis in SS LepR mutant rats versus SS rats, and chronic treatment with abatacept significantly reduced these renal abnormalities in SS LepR mutant rats. These data suggest that renal T-cell activation contributes to the early progression of renal injury associated with prepubertal obesity.
Subject(s)
Abatacept , Kidney , Obesity , Rats, Inbred Dahl , Receptors, Leptin , T-Lymphocytes , Animals , Abatacept/pharmacology , Obesity/drug therapy , T-Lymphocytes/drug effects , T-Lymphocytes/immunology , T-Lymphocytes/metabolism , Kidney/pathology , Kidney/drug effects , Kidney/metabolism , Receptors, Leptin/genetics , Receptors, Leptin/metabolism , Receptors, Leptin/deficiency , Male , Rats , Disease Progression , Disease Models, Animal , Proteinuria/drug therapy , Kidney Diseases/pathology , Kidney Diseases/drug therapy , Kidney Diseases/metabolism , Sexual Maturation/drug effectsABSTRACT
The strongest genetic risk factor for rheumatoid arthritis (RA) has been known as HLA-DRB1 based on amino acid positions 11, 71, and 74. This study analyzed the association between specific HLA-DRB1 locus and treatment response to abatacept or TNF inhibitors (TNFi) in patients with seropositive RA. A total of 374 Korean RA patients were treated with abatacept (n = 110) or TNFi (n = 264). Associations between HLA-DRB1 and treatment response after 6 months were analyzed using multivariable logistic regression. Seropositive RA patients with HLA-DRB1 shared epitope (SE) had a favorable response to abatacept (OR = 3.67, P = 0.067) and an inversely associated response to TNFi (OR 0.57, P = 0.058) based on EULAR response criteria, but the difference was not statistically significant in comparison to those without SE. In analyses using amino acid positions of HLA-DRB1, a significant association was found between valine at amino acid position 11 of SE and good response to abatacept (OR = 6.46, P = 5.4 × 10-3). The VRA haplotype also showed a good response to abatacept (OR = 4.56, P = 0.013), but not to TNFi. Our results suggest that treatment response to abatacept or TNFi may differ depending on HLA-DRB1 locus in seropositive RA, providing valuable insights for selecting optimal therapy.
Subject(s)
Arthritis, Rheumatoid , Tumor Necrosis Factor Inhibitors , Humans , Abatacept/pharmacology , Abatacept/therapeutic use , Abatacept/genetics , HLA-DRB1 Chains/genetics , Tumor Necrosis Factor Inhibitors/therapeutic use , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/genetics , Epitopes/genetics , Amino Acids/genetics , Alleles , Genetic Predisposition to DiseaseABSTRACT
Allogeneic hematopoietic cell transplantation (allo-HCT) offers a curative option for patients with certain non-malignant hematological diseases. High-dose post-transplant cyclophosphamide (PT-Cy) (200 mg/kg) and sirolimus (3 mg/kg), (HiC) synergistically induce stable mixed chimerism. Further, sirolimus and cytotoxic T lymphocyte-associated antigen-4 immunoglobulin (CTLA4-Ig), also known as Abatacept (Aba), promote immune tolerance and allograft survival. Here, in a major histocompatibility complex (MHC)-mismatched allo-HCT murine model, we combined Aba and/or T-cell depleting anti-Thy1.2 (Thy) with a lower dose of PT-Cy (50 mg/kg) and Sirolimus (3 mg/kg), (LoC). While mice in the LoC group showed graft rejection, the addition of Thy to LoC induced similar donor chimerism levels when compared to the HiC group. However, the addition of Aba to LoC led to graft acceptance only in younger mice. When Thy was added to the LoC+Aba setting, graft acceptance was restored in both age groups. Engrafted groups displayed significantly reduced frequencies of recipient-specific interferon-γ-producing T cells as well as an increased frequency in regulatory T cells (Tregs) except in the LoC+Aba group. Splenocytes from engrafted mice showed no proliferation upon restimulation with Balb/c stimulators. Collectively, in combination with Aba or Thy, LoC may be considered to reduce graft rejection in patients who undergo allo-HCT.
Subject(s)
Abatacept , Cyclophosphamide , Lymphocyte Depletion , Sirolimus , Animals , Cyclophosphamide/pharmacology , Sirolimus/pharmacology , Mice , Abatacept/pharmacology , Abatacept/therapeutic use , Hematopoietic Stem Cell Transplantation/methods , Mice, Inbred BALB C , Transplantation Chimera , Transplantation, Homologous/methods , AllograftsABSTRACT
BACKGROUND: Desensitization is one of the strategies to reduce antibodies and facilitate heart transplantation in highly sensitized patients. We describe our center's desensitization experience with combination of plasma cell (PC) depletion therapy (with proteasome inhibitor or daratumumab) and costimulation blockade (with belatacept). METHODS: We reviewed five highly sensitized patients who underwent desensitization therapy with plasma cell depletion and costimulation blockade. We evaluated the response to therapy by measuring the changes in cPRA, average MFI, and number of positive beads > 5000MFI. RESULTS: Five patients, mean age of 56 (37-66) years with average cPRA of 98% at 5000 MFI underwent desensitization therapy. After desensitization, mean cPRA decreased from 98% to 70% (p = .09), average number of beads > 5000 MFI decreased from 59 to 37 (p = .15), and average MFI of beads > 5000 MFI decreased from 16713 to 13074 (p = .26). CONCLUSION: Combined PC depletion and CoB could be a reasonable strategy for sustained reduction in antibodies in highly sensitized patients being listed for heart transplantation.
Subject(s)
Heart Transplantation , Plasma Cells , Humans , Middle Aged , Abatacept/therapeutic use , Abatacept/pharmacology , Desensitization, Immunologic , Graft Rejection/etiology , Graft Rejection/prevention & control , HLA Antigens , Isoantibodies , Proteasome Inhibitors , Adult , AgedABSTRACT
BACKGROUND: Rheumatoid arthritis (RA) patients seropositive for hepatitis B core antibody (HBcAb) and negative for hepatitis B surface antigen (HBsAg) are at risk of hepatitis B virus (HBV) reactivation when treated with biologic or targeted synthetic (b/ts) disease-modifying antirheumatic drugs (DMARDs). The study aims to investigate the risk in this population. METHODS: From January 2004 through December 2020, 1068 RA patients undergoing b/tsDMARDs therapy and 416 patients with HBsAg-/HBcAb+ were enrolled. Factors associated with HBV reactivation were analysed. RESULTS: During 2845 person-years of follow-up, 27 of 416 (6.5%,9.5 per 1000 person-years) patients developed HBV reactivation, with a cumulative rate of HBV reactivation of 3.5% at 5 years, 6.1% at 10 years and 24.2% at 17 years. The median interval from beginning b/tsDMARDs to HBV reactivation was 85 months (range: 9-186 months). The risk of HBV reactivation varied by type of b/tsDMARD, with rituximab having the highest risk (incidence rate: 48.3 per 1000 person-years), followed by abatacept (incidence rate: 24.0 per 1000 person-years). In multivariate analysis, rituximab (adjusted hazard ratio [aHR]: 15.77, 95% confidence interval [CI]: 4.12-60.32, p = .001), abatacept (aHR: 9.30, 1.83-47.19, p = .007), adalimumab (aHR: 3.86, 1.05-14.26, p = .04) and negative baseline HBV surface antibody (anti-HBs, <10 mIU/mL) (aHR: 3.89, 1.70-8.92, p < .001) were independent risk factors for HBV reactivation. CONCLUSION: HBsAg-/HBcAb+ RA patients are susceptible to HBV reactivation during b/tsDMARD therapy. Those with negative baseline anti-HBs and those on certain b/tsDMARDs, such as rituximab, abatacept and adalimumab, have high reactivation risks. Risk stratification and management should be based on the patient's baseline anti-HBs titre and type of therapy.
Subject(s)
Antirheumatic Agents , Arthritis, Rheumatoid , Biological Products , Hepatitis B , Humans , Hepatitis B virus , Hepatitis B Surface Antigens , Rituximab/adverse effects , Adalimumab/adverse effects , Abatacept/therapeutic use , Abatacept/pharmacology , Hepatitis B/drug therapy , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/complications , Antirheumatic Agents/adverse effects , Hepatitis B Antibodies , Virus ActivationABSTRACT
Abatacept (CTLA4-Ig)-a monoclonal antibody which restricts T cell activation-is an effective treatment for rheumatoid arthritis (RA). Nevertheless, only 50% of RA patients attain clinical responses, while predictors of response are rather limited. Herein, we aimed to investigate for early biomarkers of response to abatacept, based on a detailed immunological profiling of peripheral blood (PB) cells and serum proteins. We applied flow cytometry and proteomics analysis on PB immune cells and serum respectively, of RA patients starting abatacept as the first biologic agent. After 6 months of treatment, 34.5% of patients attained response. At baseline, Th1 and FoxP3+ T cell populations were positively correlated with tender joint counts (p-value = 0.047 and p-value = 0.022, respectively). Upon treatment, CTLA4-Ig effectively reduced the percentages of Th1 and Th17 only in responders (p-value = 0.0277 and p-value = 0.0042, respectively). Notably, baseline levels of Th1 and myeloid cell populations were significantly increased in PB of responders compared to non-responders (p-value = 0.009 and p-value = 0.03, respectively). Proteomics analysis revealed that several inflammatory mediators were present in serum of responders before therapy initiation and strikingly 10 amongst 303 serum proteins were associated with clinical responses. Finally, a composite index based on selected baseline cellular and proteomics' analysis could predict response to abatacept with a high sensitivity (90%) and specificity (88.24%).
Subject(s)
Antirheumatic Agents , Arthritis, Rheumatoid , Humans , Abatacept/pharmacology , Abatacept/therapeutic use , Antirheumatic Agents/pharmacology , Antirheumatic Agents/therapeutic use , Inflammation Mediators , Myeloid CellsABSTRACT
Germline CTLA-4 deficiency causes severe autoimmune diseases characterized by dysregulation of Foxp3+ Tregs, hyper-activation of effector memory T cells, and variable forms autoimmune cytopenia including gradual loss of B cells. Cancer patients with severe immune-related adverse events (irAE) after receiving anti-CTLA-4/PD-1 combination immunotherapy also have markedly reduced peripheral B cells. The immunological basis for B cell loss remains unexplained. Here, we probe the decline of B cells in human CTLA-4 knock-in mice by using anti-human CTLA-4 antibody Ipilimumab conjugated to a drug payload emtansine (Anti-CTLA-4 ADC). The anti-CTLA-4 ADC-treated mice have T cell hyper-proliferation and their differentiation into effector cells which results in B cell depletion. B cell depletion is mediated by both CD4 and CD8 T cells and at least partially rescued by anti-TNF-alpha antibody. These data revealed an unexpected antagonism between T and B cells and the importance of regulatory T cells in preserving B cells.
Subject(s)
Abatacept , B-Lymphocytes , T-Lymphocytes, Regulatory , B-Lymphocytes/drug effects , B-Lymphocytes/immunology , Abatacept/pharmacology , Animals , Mice , CTLA-4 Antigen/genetics , CTLA-4 Antigen/immunology , Lymphocyte Depletion , T-Lymphocytes, Regulatory/drug effects , T-Lymphocytes, Regulatory/immunology , Apoptosis/drug effects , Immunoglobulins/blood , Immunoglobulins/immunology , CHO Cells , Cricetulus , Mice, Inbred C57BL , Male , FemaleABSTRACT
Rheumatoid arthritis (RA) causes bone loss, only partly related to inflammation. The impact of RA treatments on bone metabolism and their ability to mitigate bone loss remains uncertain. The primary goal of our study was to examine the influence of abatacept on serum levels of markers and regulators involved in bone turnover. Secondary objectives included evaluating changes in bone mineral density (BMD), bone health parameters, erosions, and exploring potential correlations among these parameters. We conducted a prospective observational study on patients with active seropositive RA failure to biological disease modifying anti-rheumatic drugs initiating treatment with abatacept. We measured at baseline and after 1, 2, 3, 6, 9 and 12 months: serum bone turnover markers (CTX, P1nP, B-ALP), bone modulators (Dkk-1, sclerostin, vitamin D, PTH, OPG and RANKL), BMD and radiographic parameters (modified Sharp van der Heijde score [mSvdH], bone health index [BHI] and metacarpal index [MCI]). Disease activity and glucocorticoid intake was monitored. 33 patients were enrolled in the study. We found a significant increase in markers of bone formation (B-ALP and P1nP) from baseline to M6 and M12. PTH increased significantly at M6 but not at M12. All other bone markers and modulators did not change. We found a significant decrease in BHI and MCI from baseline to M12 (median difference - 0.17 95% CI - 0.42 to - 0.10, p 0.001 and - 0.09 95% CI - 0.23 to - 0.07, respectively). BMD at femoral neck transitorily decreased at M6 (mean difference - 0.019 g/cm2 95% CI - 0.036 to - 0.001 p 0.04). BMD at total hip, lumbar spine and mSvdH score did not change significantly. P1nP delta at M12 correlated with delta mSvdH. Treatment with abatacept was associated with a significant increase in bone formation markers. The secondary and transient increase in PTH serum levels may be responsible of the transitory bone loss.
Subject(s)
Antirheumatic Agents , Arthritis, Rheumatoid , Bone Diseases, Metabolic , Humans , Abatacept/pharmacology , Abatacept/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/drug therapy , Biomarkers , Bone and Bones/diagnostic imaging , Bone Density , Bone Diseases, Metabolic/chemically induced , Bone Diseases, Metabolic/drug therapy , Bone Remodeling , Prospective StudiesABSTRACT
The humoral response mediated by alloantibodies directed against donor HLA molecules (DSAs) is one of the main causes of graft loss in kidney transplantation. Understanding the pathophysiology leading to humoral kidney rejection as the development of therapeutic tools is therefore a main objective in the field of solid organ transplantation and necessitate adapted experimental models. Among the immunosuppressive agents used in renal transplantation, belatacept, a fusion protein targeting T costimulatory molecules has shown its ability to prevent more efficiently the secretion of DSA by different mechanisms including a direct action on plasma cells but also on B lymphocytes and follicular helper T lymphocytes (Tfh) cooperation. This cellular cooperation occurs within germinal centers (GC), the seat of B lymphocytes differentiation. Here, we aimed to develop a dedicated mouse model in which human GC would be functional to study the effect of belatacept on GC formation and the ability of B lymphocytes to secrete immunoglobulin. We next demonstrate that belatacept inhibits the formation of these GCs, by inhibiting the frequency of Tfh and B lymphocytes. This alters the B maturation and therefore the generation of plasma cells and consequently, immunoglobulin secretion.
Subject(s)
B-Lymphocytes , Germinal Center , Humans , Animals , Mice , Abatacept/pharmacology , Immunosuppressive Agents/pharmacology , Plasma CellsABSTRACT
Combined antigen-specific T cell receptor stimulation and costimulation are needed for complete T cell activation. Belatacept and abatacept are nondepleting fusion proteins blocking CD28/B7 costimulation, whereas siplizumab is a depleting antiCD2 immunoglobulin G1 monoclonal antibody targeting CD2/CD58 costimulation. Herein, the effect of siplizumab combination therapy with abatacept or belatacept on T cell alloreactivity in mixed lymphocyte reactions was investigated. In contrast to monotherapy, the combination of siplizumab with belatacept or abatacept induced near-complete suppression of T cell proliferation and increased the potency of siplizumab-mediated T cell inhibition. Furthermore, dual targeting of CD2 and CD28 costimulation enhanced the selective depletion of memory T cells compared with monotherapy. Although siplizumab monotherapy leads to significant regulatory T cell enrichment, high doses of cytotoxic T-lymphocyte-associated antigen 4 and a human IgG1 Fc fragment in the combination therapy reduced this effect. These results support the clinical evaluation of dual costimulation blockade, combining siplizumab with abatacept or belatacept, for the prophylaxis of organ transplant rejection and improvement of long-term outcomes following transplantation. Ongoing investigative research will elucidate when other forms of siplizumab-based dual costimulatory blockade may be able to induce similarly strong inhibition of T cell activation although still allowing for enrichment of regulatory T cells.
Subject(s)
CD28 Antigens , Kidney Transplantation , Humans , Abatacept/pharmacology , Abatacept/therapeutic use , Kidney Transplantation/methods , Antibodies, Monoclonal, Humanized/pharmacology , Immunosuppressive Agents/pharmacology , Immunosuppressive Agents/therapeutic use , Graft Rejection/drug therapy , Graft Rejection/prevention & controlABSTRACT
Among sensitized patients awaiting a transplant, females are disproportionately represented, partly because of pregnancy-induced sensitization. Using female NHPs sensitized by pregnancy alone, we examined the efficacy of costimulation blockade and proteasome inhibition for desensitization. Three animals received no desensitization (control), and seven animals received weekly carfilzomib (27 mg/m2) and belatacept (20 mg/kg) before kidney transplantation. All animals received renal allografts from crossmatch-positive/maximally MHC-mismatched donors. Controls and three desensitized animals received tacrolimus-based immunosuppression. Four desensitized animals received additional belatacept with tacrolimus-based immunosuppression. Multiparous females had less circulating donor-specific antibody when compared to skin-sensitized males before transplantation. While females receiving desensitization showed only a marginal survival benefit over control females (MST = 11 days versus 63 days), additional belatacept to posttransplant maintenance significantly prolonged graft survival (MST > 164 days) and suppressed posttransplant DSA and circulating follicular helper T-like cells. This combination of therapies demonstrates great potential to reduce antibody-mediated rejection in sensitized recipients.
Subject(s)
Immunosuppressive Agents , Kidney Transplantation , Male , Pregnancy , Animals , Female , Abatacept/pharmacology , Abatacept/therapeutic use , Immunosuppressive Agents/pharmacology , Immunosuppressive Agents/therapeutic use , Kidney Transplantation/adverse effects , Tacrolimus/pharmacology , Tacrolimus/therapeutic use , Graft Rejection/prevention & control , AntibodiesABSTRACT
BACKGROUND/AIMS: Although the conversion from tacrolimus (TAC) to cytotoxic T-lymphocyte-associated antigen 4-immunoglobulin (CTLA4-Ig) is effective in reducing TAC-induced nephrotoxicity, it remains unclear whether CTLA4-Ig has a direct effect on TAC-induced renal injury. In this study, we evaluated the effects of CTLA4-Ig on TAC-induced renal injury in terms of oxidative stress. METHODS: In vitro study was performed to assess the effect of CTLA4-Ig on TAC-induced cell death, reactive oxygen species (ROS), apoptosis, and the protein kinase B (AKT)/forkhead transcription factor (FOXO) 3 pathway in human kidney 2 cells. In the in vivo study, the effect of CTLA4-Ig on TAC-induced renal injury was evaluated using renal function, histopathology, markers of oxidative stress (8-hydroxy-2'-deoxyguanosine) and metabolites (4-hydroxy-2-hexenal, catalase, glutathione S-transferase, and glutathione reductase), and activation of the AKT/FOXO3 pathway with insulin-like growth factor 1 (IGF-1). RESULTS: CTLA4-Ig significantly decreased cell death, ROS, and apoptosis caused by TAC. TAC treatment increased apoptotic cell death and apoptosis-related proteins (increased Bcl-2-associated X protein and caspase-3 and decreased Bcl-2), but it was reversed by CTLA4-Ig treatment. The activation of p-AKT and p-FOXO3 by TAC decreased with CTLA4-Ig treatment. TAC-induced renal dysfunction and oxidative marker levels were significantly improved by CTLA4-Ig in vivo. Concomitant IGF-1 treatment abolished the effects of CTLA4-Ig. CONCLUSION: CTLA4-Ig has a direct protective effect on TAC-induced renal injury via the inhibition of AKT/FOXO3 pathway.
Subject(s)
Renal Insufficiency , Tacrolimus , Rats , Humans , Animals , Tacrolimus/pharmacology , Abatacept/pharmacology , Abatacept/metabolism , Insulin-Like Growth Factor I/metabolism , Insulin-Like Growth Factor I/pharmacology , Proto-Oncogene Proteins c-akt , Reactive Oxygen Species , Rats, Sprague-Dawley , Signal Transduction , Oxidative Stress , Apoptosis , Apoptosis Regulatory Proteins/metabolism , Forkhead Box Protein O3/metabolism , CTLA-4 AntigenABSTRACT
The adoptive transfer of insulin-producing cells (IPCs) is one of the promising treatments for insulin-dependent diabetes mellitus. While the use of allogeneic cell resources is inevitable in the case of a series of patients, alloimmune responses are a major barrier ahead of the successful implementation of allogeneic therapeutic cells. This study is aimed at evaluating the potential of CTLA4-Ig, as an approved immunomodulatory biologic, in protecting the IPCs against allogeneic immune responses. The C57BL/6 and BALB/c mice were used to establish a murine model of allogeneic cell transplantation. The mouse bone-marrow-derived mesenchymal stem cells were in vitro differentiated into IPCs, and the in vitro as well as the in vivo immune responses against IPCs were evaluated in the presence and absence of CTLA4-Ig. The allogeneic IPCs induced the in vitro activation of CD4+ T-cells, IFN-γ release, and the proliferation of lymphocytes, which all were controlled by CTLA4-Ig. Upon in vivo transfer of IPC into an allogeneic host, the splenic CD4+ and CD8+ T-cells exhibited a significant activation, and there was a significant donor-specific antibody response. Either of the mentioned cellular and humoral responses were modulated by a CTLA4-Ig regimen. This regimen also reduced the infiltration of CD3+ T-cells into the IPC injection site along with the improved overall survival of diabetic mice. CTLA4-Ig could be a complementary therapy for improving the efficacy of allogeneic IPC therapy through modulating the cellular and humoral responses that can lead to prolonged durability of IPCs within an allogeneic host.
Subject(s)
Diabetes Mellitus, Experimental , Hematopoietic Stem Cell Transplantation , Immunoconjugates , Insulins , Animals , Mice , Abatacept/pharmacology , Abatacept/therapeutic use , CD8-Positive T-Lymphocytes , CTLA-4 Antigen , Diabetes Mellitus, Experimental/therapy , Disease Models, Animal , Immunity , Immunoconjugates/pharmacology , Mice, Inbred BALB C , Mice, Inbred C57BLABSTRACT
CD28 and CTLA4 are T cell coreceptors that competitively engage B7 ligands CD80 and CD86 to control adaptive immune responses. While the role of CTLA4 in restraining CD28 costimulatory signaling is well-established, the mechanism has remained unclear. Here, we report that human T cells acquire antigen-presenting-cell (APC)-derived B7 ligands and major histocompatibility complex (MHC) via trogocytosis through CD28:B7 binding. Acquired MHC and B7 enabled T cells to autostimulate, and this process was limited cell-intrinsically by CTLA4, which depletes B7 ligands trogocytosed or endogenously expressed by T cells through cis-endocytosis. Extending this model to the previously proposed extrinsic function of CTLA4 in human regulatory T cells (Treg), we show that blockade of either CD28 or CTLA4 attenuates Treg-mediated depletion of APC B7, indicating that trogocytosis and CTLA4-mediated cis-endocytosis work together to deplete B7 from APCs. Our study establishes CTLA4 as a cell-intrinsic molecular sink that limits B7 availability on the surface of T cells, with implications for CTLA4-targeted therapy.
Subject(s)
CD28 Antigens , Immunoconjugates , Humans , CTLA-4 Antigen/metabolism , CD28 Antigens/metabolism , Antigens, CD/metabolism , Ligands , Antigens, Differentiation , Abatacept/pharmacology , B7-2 Antigen , Membrane Glycoproteins/metabolism , B7-1 Antigen/metabolism , Cell Adhesion MoleculesABSTRACT
OBJECTIVE: Previous studies showed that inhibiting lymphocyte costimulation reduces declining ß-cell function in individuals newly diagnosed with type 1 diabetes. We tested whether abatacept would delay or prevent progression of type 1 diabetes from normal glucose tolerance (NGT) to abnormal glucose tolerance (AGT) or to diabetes and the effects of treatment on immune and metabolic responses. RESEARCH DESIGN AND METHODS: We conducted a phase 2, randomized, placebo-controlled, double-masked trial of abatacept in antibody-positive participants with NGT who received monthly abatacept/placebo infusions for 12 months. The end point was AGT or diabetes, assessed by oral glucose tolerance tests. RESULTS: A total of 101 participants received abatacept and 111 placebo. Of these, 81 (35 abatacept and 46 placebo) met the end point of AGT or type 1 diabetes diagnosis (hazard ratio 0.702; 95% CI 0.452, 1.09; P = 0.11) The C-peptide responses to oral glucose tolerance tests were higher in the abatacept arm (P < 0.03). Abatacept reduced the frequency of inducible T-cell costimulatory (ICOS)+ PD1+ T-follicular helper (Tfh) cells during treatment (P < 0.0001), increased naive CD4+ T cells, and also reduced the frequency of CD4+ regulatory T cells (Tregs) from the baseline (P = 0.0067). Twelve months after treatment, the frequency of ICOS+ Tfh, naive CD4+ T cells, and Tregs returned to baseline. CONCLUSIONS: Although abatacept treatment for 1 year did not significantly delay progression to glucose intolerance in at-risk individuals, it impacted immune cell subsets and preserved insulin secretion, suggesting that costimulation blockade may modify progression of type 1 diabetes.