Project description:T cell-based therapies have been widely explored for the treatment of cancer and chronic infection, but B cell-based therapies have remained largely unexplored. To study the effect of B cell therapy, we adoptively transferred virus-specific B cells into mice that were chronically infected with lymphocytic choriomeningitis virus (LCMV). Adoptive transfer of virus-specific B cells resulted in increase in antibody titers and reduction of viral loads. Importantly, the efficacy of B cell therapy was partly dependent on antibody effector functions, and was improved by co-transferring virus-specific CD4 T cells. These findings provide a proof-of-concept that adoptive B cell therapy can be effective for the treatment of chronic infections, but provision of virus-specific CD4 T cells may be critical for optimal virus neutralization.
Project description:Delayed immune reconstitution and the consequently high rates of leukemia relapse and infectious complications are the main limitations of haploidentical hematopoietic stem cell transplantation. Donor T cell addback can accelerate immune reconstitution but the therapeutic window between graft-vs.-host disease and protective immunity is very narrow in the haploidentical transplant setting. Hence, strategies to improve the safety and efficacy of adoptive T cell transfer are particularly relevant in this setting. Adoptive T cell transfer strategies in haploidentical transplantation include the use of antigen-specific T cells, allodepletion and alloanergy induction, immune modulation by the co-infusion of regulatory cell populations, and the use of safety switch gene-modified T cells. Whilst common principles apply, there are features that are unique to haploidentical transplantation, where HLA-mismatching directly impacts on immune reconstitution, and shared vs. non-shared HLA-allele can be an important consideration in antigen-specific T cell therapy. This review will also present an update on safety switch gene-modified T cells, which can be conditionally deleted in the event of severe graft- vs.-host disease or other adverse events. Herpes Virus Simplex Thymidine Kinase (HSVtk) and inducible caspase-9 (iCasp9) are safety switches that have undergone multicenter studies in haploidentical transplantation with encouraging results. These gene-modified cells, which are trackable long-term, have also provided important insights on the fate of adoptively transferred T cells. In this review, we will discuss the biology of post-transplant T cell immune reconstitution and the impact of HLA-mismatching, and the different cellular therapy strategies that can help accelerate T cell immune reconstitution after haploidentical transplantation.
Project description:Purpose of reviewPeripheral T cell lymphomas (PTCLs) are a heterogeneous group of diseases and represent approximately 10-15% of all non-Hodgkin lymphomas. Multiagent chemotherapy with a CHOP (cyclophosphamide, adriamycin, vincristine, prednisone)-like regimen is the current standard of care in the frontline setting, but outcomes for PTCL patients generally remain poor. Strategies used to improve survival and reduce the risk of relapse in PTCL patients include autologous hematopoietic cell transplant (autoHCT) and allogeneic HCT (alloHCT). Due to the relative rarity of these diseases, the evidence supporting the use of autoHCT and alloHCT is based on retrospective and single-arm prospective studies. Novel targeted therapies are now being incorporated into the treatment of PTCL, and they may play important roles in improving upon current standards of care. Herein, we summarize the evidence supporting HCT for the treatment of the most common PTCL histologic subtypes and highlight novel treatment strategies aimed at improving outcomes for these patients, including cutting-edge approaches using chimeric antigen receptor T cells (CAR-T).Recent findingsGiven recent improvements in OS and PFS in CD30+ PTCL using the drug-antibody conjugate brentuximab vedotin (BV), new questions arise regarding the impact of BV on consolidative autoHCT, and its role as a maintenance therapy. Multiple histone deacetylase inhibitors (HDACis) have been approved for the treatment of relapsed/refractory PTCL, and these agents are being incorporated into HCT approaches, both in the frontline and maintenance settings. Early data incorporating these agents into novel conditioning regimens have been reported, and emerging evidence from recent trials suggests that CART cell therapies may prove effective in relapsed/refractory PTCL. The recommended treatment strategy in non-ALK+ PTCL remains induction with a CHOP-like regimen followed by consolidative autoHCT in first remission. In the relapsed/refractory setting, salvage chemotherapy followed by HCT (autoHCT or alloHCT depending on histologic subtype and HCT history) offers the only potential for cure or long-term remission. Ample room for improvement remains in the treatment of patients with PTCL, and novel treatment strategies incorporating targeted agents and CAR-T therapy may help to address the unmet needs of this patient population.
Project description:Despite advances in anti-infective agents, viral and fungal infections after hematopoietic stem cell transplantation (HSCT) continue to cause life-threatening complications that limit the success of HSCT. Early adoptive T-cell immunotherapy studies showed that administration of allogeneic virus-specific cytotoxic T lymphocytes (vCTL) can prevent and control viral infections and reconstitute antiviral immunity to cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Advances in immunobiology, in vitro culture technology, and current good manufacturing practice (cGMP) have provided opportunities for advancing adoptive cell therapy for viral infections: (1) T cells have been expanded targeting multiple pathogens; (2) vCTL production no longer requires viral infection or viral vector transduction of antigen-presenting cells (APCs); (3) the source of lymphocytes is no longer restricted to donors who are immune to the pathogens; (4) naive T cells have been redirected with chimeric antigen receptor T cells (CARTs) or armed with bispecific antibody-armed T cells (BATs) to mediate vCTL activity; (5) these technologies could be combined to targeted multiple viral or fungal pathogens; and (6) pathogen-specific T-cell products manufactured from third parties and banked for “off-the-shelf” use post-HSCT may soon become a reality.
Project description:In relapsed and refractory multiple myeloma (MM), adoptive cell therapies (ACT) including CAR-T-cells are under clinical investigation. However, relapse due to T-cell exhaustion or limited persistence is an obstacle. Before ACT are considered in MM, high-dose (HD) melphalan followed by autologous stem-cell transplantation (autoSCT) has been administered in most clinical situations. Yet, the impact of HD chemotherapy on T-cells in MM with respect to ACT is unclear. In this study, T-lymphocytes' phenotypes, expansion properties, lentiviral transduction efficacy, and gene expression were examined with special respect to patients following HD melphalan. Significant impairment of T-cells' expansion and transduction rates could be demonstrated. Expansion was diminished due to inherent disadvantages of the predominant T-cell phenotype but restored over time. The quantitative fraction of CD27-/CD28- T-cells before expansion was predictive of T-cell yield. Following autoSCT, the transduction efficacy was reduced by disturbed lentiviral genome integration. Moreover, an unfavorable T-cell phenotype after expansion was demonstrated. In initial analyses of CD107a degranulation impaired T-cell cytotoxicity was detected in one patient following melphalan and autoSCT. The findings of our study have potential implications regarding the time point of leukapheresis for CAR-T-cell manufacturing. Our results point to a preferred interval of more than 3 months until patients should undergo cell separation for CAR-T therapy in the specific situation post-HD melphalan/autoSCT. Monitoring of CD27-/CD28- T-cells, has the potential to influence clinical decision making before apheresis in MM.
Project description:HLA-DPB1 antigens are mismatched in about 80% of allogeneic hematopoietic stem cell transplantations from HLA 10/10 matched unrelated donors and were shown to be associated with a decreased risk of leukemia relapse. We recently developed a reliable in vitro method to generate HLA-DPB1 mismatch-reactive CD4 T-cell clones from allogeneic donors. Here, we isolated HLA-DPB1 specific T cell receptors (TCR DP) and used them either as wild-type or genetically optimized receptors to analyze in detail the reactivity of transduced CD4 and CD8 T cells toward primary AML blasts. While both CD4 and CD8 T cells showed strong AML reactivity in vitro, only CD4 T cells were able to effectively eliminate leukemia blasts in AML engrafted NOD/SCID/IL2Rγc-/- (NSG) mice. Further analysis showed that optimized TCR DP and under some conditions wild-type TCR DP also mediated reactivity to non-hematopoietic cells like fibroblasts or tumor cell lines after HLA-DP upregulation. In conclusion, T cells engineered with selected allo-HLA-DPB1 specific TCRs might be powerful off-the-shelf reagents in allogeneic T-cell therapy of leukemia. However, because of frequent (common) cross-reactivity to non-hematopoietic cells with optimized TCR DP T cells, safety mechanisms are mandatory.
Project description:After allogeneic hematopoietic stem cell transplantation (HSCT), donor lymphocytes may contribute to the regression of hematological malignancies and select solid tumors, a phenomenon referred to as the graft-versus-tumor effect (GVT). However, this immunologic reaction is frequently limited by either poor specificity resulting in graft-versus-host disease or the frequency of tumor-specific T cells being too low to induce a complete and sustained anti-tumor response. Over the past 2 decades, it has become clear that the driver of GVT following allogeneic HSCT is T-cell-mediated recognition of antigens presented on tumor cells. With that regard, even though the excitement for using HSCT in solid tumors has declined, clinical trials of HSCT in solid tumors provided proof of concept and valuable insights leading to the discovery of tumor antigens and the development of targeted adoptive cell therapies for cancer. In this article, we review the results of clinical trials of allogeneic HSCT in solid tumors. We focus on lessons learned from correlative studies of these trials that hold the potential for the creation of tumor-specific immunotherapies with greater efficacy and safety for the treatment of malignancies.
Project description:BackgroundCytomegalovirus (CMV) reactivation after unmanipulated haploidentical stem cell transplantation (SCT) frequently occurs, causing life-threatening morbidities and transplantation failure. Pre-emptive therapy upon the detection of CMV viremia using antiviral agents is currently the standard of care but it was associated with significant toxicity. The CMV antigen-specific cytotoxic T lymphocyte therapy was limited by the time-consuming manufacture process and relatively low success rate. More effective and safer approaches for the treatment of CMV reactivation after haploidentical SCT are in urgent need.MethodsA single-arm, open-label, phase I clinical trial evaluating the safety and efficacy of CMV-targeting T cell receptor-engineered T (CMV-TCR-T) cell therapy as the first-line pre-emptive therapy for patients with CMV reactivation after haploidentical peripheral blood SCT (PBSCT) was conducted in the Chinese PLA General Hospital. Six patients with CMV reactivation after haploidentical SCT were adoptively transferred by one to three doses of SCT donors-derived CMV-TCR-T cells. This trial was a dose-escalation study with doses ranging from 1×103 CMV-TCR-T cells/kg body weight per dose to 5×105 CMV-TCR-T cells/kg per dose.ResultsExcept for the grade 1 cytokine release syndrome observed in one patient and mild fever in two patients, no other adverse events were observed. Four patients had response within a month after CMV-TCR-T cell infusion without the administration of any antiviral agents. The other two patients who initially did not respond to CMV-TCR-T cell therapy had salvage ganciclovir and foscarnet administration and then had rapid CMV clearance. The CMV-TCR-T cells displayed overall robust expansion and persistence in the peripheral blood after infusion. The CMV-TCR-T cells were first detected in the peripheral blood of these patients 3-7 days after the first dose of CMV-TCR-T infusion, rapidly expanded and persisted for at least 1-4 months, providing long-term protection against CMV reactivation. In one patient, the CMV-TCR-T cells started to expand even when the anti-graft-versus-host disease reagents were still being used, further indicating the proliferation potential of CMV-TCR-T cells.ConclusionsOur study first showed CMV-TCR-T cell as a highly feasible, safe and effective first-line pre-emptive treatment for CMV reactivation after haploidentical PBSCT.Trial registration numberClinicalTrials.gov Registry (NCT05140187).
Project description:Highly active anti-retroviral treatment has changed the dimensions of the outcomes for patients suffering from human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS). However, HIV infection is still an ailment which is spreading throughout the world extensively. Given the confinements of the present restorative methodologies and the non-availability of any strategic vaccination against HIV, there is a squeezing need to build a therapeutic treatment. Viral tropism for HIV includes CD4+ cells, macrophages, and microglial cells, and it is through binding with co-receptors C-C chemokine receptor type 5 (CCR5) and C-X-C chemokine receptor type 4 (CXCR4). While these cell types are present in all individuals, there are rare cases that stayed uninfected even after getting exposed to an overwhelming load of HIV. Research revealed a homozygous 32-base pair deletion (Δ32/Δ32) in CCR5. After careful consideration, a hypothesis was proposed a few years back that a cure for HIV disease is possible, through hematopoietic stem cells transplantation from a donor homozygous for the CCR5-Δ32 deletion. Hematopoietic stem cell (HSC) based quality treatment may serve as a promising tool as these perpetual, self-renewing progenitor cells could be modified to oppose HIV infection. If done properly, the changed HSCs would offer the permanent creation of genetically modified cells that are resistant to HIV infection and/or have improved hostility to viral action which will eventually clear the contaminated cells. The purpose of this review is to concentrate on two facets of HSC genetic treatment for potentially life-threatening HIV infection: building HIV-resistant cells and designing cells that can target HIV disease. These two strategic approaches can be the frontline of a quality treatment plan against HIV infection and, as an individual treatment or a combination thereof, has been proposed to possibly destroy HIV altogether.