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Allogeneic virus-specific T cell (VST) therapies offer distinct advantages, including scalability, rapid deployment, and manufacturing consistency, and have demonstrated efficacy in multiple clinical trials. However, identifying VST products with high therapeutic potential remains a major hurdle. Here, we present a multidimensional analytical platform that integrates in vitro and in vivo anti-viral reactivity, T cell receptor (TCR) repertoire analysis, gene expression profiling, immunophenotyping, and functional validation in a humanized mouse model. Epstein-Barr virus (EBV)-specific T cells expanded from HLA-diverse healthy donors consistently enriched for TCRs targeting EBV-encoded antigens. Transcriptomic and high-dimensional flow cytometric analyses revealed a distinct effector-associated signature. Importantly, this integrative approach uncovered correlative biomarkers of T cell potency and effector function, validated in an in vivo model of EBV-driven B cell lymphoma. These findings establish a scalable framework for the characterization of allogeneic T cell products and may inform the development of predictive metrics for in vivo efficacy. Allogeneic T cell therapies could be used in therapeutic applications because of their potential for ‘off-the-shelf’ access and standardised production. Here the authors have developed a multidimensional workflow profiling platform for EBV-specific T cell therapy and show that correlative biomarkers of T cell potency and effector function are associated with therapeutic effectiveness in xenogeneic mouse EBV-LCL models.

Adoptive T-cell immunotherapy has provided promising results in the treatment of viral complications in humans, particularly in the context of immunocompromised patients who have exhausted all other clinical options. The capacity to expand T cells from healthy immune individuals is providing a new approach to anti-viral immunotherapy, offering rapid off-the-shelf treatment with tailor-made human leukocyte antigen (HLA)-matched T cells. While most of this research has focused on the treatment of latent viral infections, emerging evidence that SARS-CoV-2-specific T cells play an important role in protection against COVID-19 suggests that the transfer of HLA-matched allogeneic off-the-shelf virus-specific T cells could provide a treatment option for patients with active COVID-19 or at risk of developing COVID-19. We initially screened 60 convalescent individuals and based on HLA typing and T-cell response profile, 12 individuals were selected for the development of a SARS-CoV-2-specific T-cell bank. We demonstrate that these T cells are specific for up to four SARS-CoV-2 antigens presented by a broad range of both HLA class I and class II alleles. These T cells show consistent functional and phenotypic properties, display cytotoxic potential against HLA-matched targets and can recognize HLA-matched cells infected with different SARS-CoV-2 variants. These observations demonstrate a robust approach for the production of SARS-CoV-2-specific T cells and provide the impetus for the development of a T-cell repository for clinical assessment.

The emergence of the SARS-CoV-2 Omicron variant has raised concerns of escape from vaccine-induced immunity. A number of studies have demonstrated a reduction in antibody-mediated neutralization of the Omicron variant in vaccinated individuals. Preliminary observations have suggested that T cells are less likely to be affected by changes in Omicron. However, the complexity of human leukocyte antigen genetics and its impact upon immunodominant T cell epitope selection suggests that the maintenance of T cell immunity may not be universal. In this study, we describe the impact that changes in Omicron BA.1, BA.2 and BA.3 have on recognition by spike-specific T cells. These T cells constitute the immunodominant CD8 + T cell response in HLA-A*29:02 + COVID-19 convalescent and vaccinated individuals; however, they fail to recognize the Omicron-encoded sequence. These observations demonstrate that in addition to evasion of antibody-mediated immunity, changes in Omicron variants can also lead to evasion of recognition by immunodominant T cell responses. The T cell response to SARS-CoV-2 is important in protection from infection. Here the authors show by concentrating on a specific HLA haplotype that mutations in SARS-CoV-2 as new variants emerge can affect T cell recognition and reduce T cell responses to the virus.

Cross‐presentation of exogenous protein antigens by B cells through the major histocompatibility complex (MHC) class I pathway in lymphoid malignancies, and transplant setting has been recognised as an important mediator of immune pathogenesis and T cell‐mediated immune regulation. However, the precise mechanism of cross‐presentation of exogenous antigens in B cells has remained unresolved. Here we have delineated a novel pathway for cross‐presentation in B cells, which involves synergistic cooperation of the proteasome and autophagy. After endocytosis, protein antigen is processed through an autophagy‐ and proteasome‐dependent pathway and CD8+ T‐cell epitopes are loaded onto MHC class I molecules within the autophagolysomal compartment rather than the conventional secretory pathway, which requires transporters associated with antigen processing‐dependent transport. Interestingly, this cross‐presentation was critically dependent on valosin‐containing protein (VCP)/p97 ATPase through its participation in autophagy. Loss of VCP/p97 ATPase was coincident with accumulation of LC3‐II and marked reduction in antigen presentation. These observations provide unique insight on how the autophagy and proteasomal degradation systems interconnect to coordinate MHC class I‐restricted cross‐presentation in B cells.

BackgroundEpstein-Barr virus (EBV), an oncogenic human gammaherpesvirus, is associated with a wide range of human malignancies of epithelial and B-cell origin. Recent studies have demonstrated promising safety and clinical efficacy of allogeneic ‘off-the-shelf’ virus-specific T-cell therapies for post-transplant viral complications.MethodsTaking a clue from these studies, we developed a highly efficient EBV-specific T-cell expansion process using a replication-deficient AdE1-LMPpoly vector that specifically targets EBV-encoded nuclear antigen 1 (EBNA1) and latent membrane proteins 1 and 2 (LMP1 and LMP2), expressed in latency II malignancies.ResultsThese allogeneic EBV-specific T cells efficiently recognized human leukocyte antigen (HLA)-matched EBNA1-expressing and/or LMP1 and LMP2-expressing malignant cells and demonstrated therapeutic potential in a number of in vivo models, including EBV lymphomas that emerged spontaneously in humanized mice following EBV infection. Interestingly, we were able to override resistance to T-cell therapy in vivo using a ‘restriction-switching’ approach, through sequential infusion of two different allogeneic T-cell therapies restricted through different HLA alleles. Furthermore, we have shown that inhibition of the programmed cell death protein-1/programmed death-ligand 1 axis in combination with EBV-specific T-cell therapy significantly improved overall survival of tumor-bearing mice when compared with monotherapy.ConclusionThese findings suggest that restriction switching by sequential infusion of allogeneic T-cell therapies that target EBV through distinct HLA alleles may improve clinical response.

The manufacture of clinical grade cellular products for adoptive immunotherapy requires ex vivo culture and expansion of human T cells. One of the key components in manufacturing of T cell therapies is human serum (HS) or fetal bovine serum (FBS), which can potentially expose immunotherapy recipient to adventitious infectious pathogens and are thus considered as non‐cGMP compliant for adoptive therapy. Here we describe a novel xeno‐free serum replacement (SR) with defined components that can be reproducibly used for the production of clinical grade T‐cell therapies in combination with several different cell culture media. Dynabeads CD3/CD28 Cell Therapy System (CTS)‐activated or antigen‐specific T cells expanded using the xeno‐free SR, CTS Immune Cell SR, showed comparable growth kinetics observed with cell culture media supplemented with HS or FBS. Importantly the xeno‐free SR supplemented medium supported the optimal expansion of T cells specific for subdominant tumour‐associated antigens and promoted expansion of T cells with central memory T‐cell phenotype, which is favourable for in vivo survival and persistence following adoptive transfer. Furthermore, T cells expanded using xeno‐free SR medium were highly amenable to lentivirus‐mediated gene transduction for potential application for gene‐modified T cells. Taken together, the CTS Immune Cell SR provides a novel platform strategy for the manufacture of clinical grade adoptive cellular therapies. Immunotherapy: Serum replacement for safer cells A new source of nutrition for cells grown in culture could improve therapies against cancer and viruses that use cultured immune cells. Before being administered to patients in a procedure known as adoptive immunotherapy, immune cells called T‐cells are usually grown in a medium that contains human or bovine serum, but this serum poses a risk of infection. Researchers led by Rajiv Khanna from the QIMR Berghofer Medical Research Institute, Australia, tested whether human or bovine serum could be effectively replaced with an alternative called CTS™ Immune Cell Serum Replacement, which contains no non‐human derived material. T‐cells grew as well in medium that contained this replacement as they did in medium that contained serum, and costs were comparable. The serum replacement enables efficient growth of T‐cells that are safer for adoptive immunotherapy.

Objectives With the ongoing emergence of SARS‐CoV‐2 variants and potential to evade vaccine‐induced neutralisation, understanding the magnitude and breadth of vaccine‐induced T‐cell immunity will be critical for the ongoing optimisation of vaccine approaches. Strategies that provide a rapid and easily translatable means of assessing virus‐specific T‐cell responses provide an opportunity to monitor the impact of vaccine rollouts in the community. In this study, we assessed whether our recently developed SARS‐CoV‐2 whole‐blood assay could be used effectively to analyse T‐cell responses following vaccination. Methods Following a median of 15 days after the first dose of the ChAdOx1‐S (AstraZeneca®) vaccine, peripheral blood was isolated from 58 participants. Blood was incubated overnight with an overlapping set of spike protein peptides and assessed for cytokine production using a cytometric bead array. Results The majority of vaccine recipients (51/58) generated a T helper 1 response (IFN‐γ and/or IL‐2) following a single dose of ChAdOx1‐S. The magnitude of the IFN‐γ and IL‐2 response strongly correlated in vaccine recipients. While the production of other cytokines was evident in individuals who did not generate IFN‐γ and IL‐2, they showed no correlation in magnitude, nor did we see a correlation between sex or age and the magnitude of the response. Conclusions The whole‐blood cytokine assay provides a rapid approach to assessing T‐cell immunity against SARS‐CoV‐2 in vaccine recipients. While the majority of participants generated a robust SARS‐CoV‐2‐specific T‐cell response following their first dose, some did not, demonstrating the likely importance of the booster dose in improving T‐cell immunity. Strategies that provide a rapid and easily translatable means of assessing SARS‐CoV‐2‐specific T‐cell responses provide an opportunity to monitor the impact of vaccine rollouts in the community. In this study, we assessed whether our recently developed SARS‐CoV‐2 whole‐blood assay could be used effectively to analyse T‐cell responses following vaccination. We demonstrated that the whole‐blood cytokine assay provides a rapid approach to assessing T‐cell immunity against SARS‐CoV‐2 in vaccine recipients.

Autologous T-cell therapy in solid organ transplant recipients with recurrent or drug-resistant CMV-associated complications is safe and may provide clinical benefit, especially when standard therapies are not effective or are contraindicated. Abstract Background Opportunistic infections including cytomegalovirus (CMV) are a major cause of morbidity and mortality in solid organ transplant (SOT) recipients. The recurrent and protracted use of antiviral drugs with eventual emergence of drug resistance represents a significant constraint to therapy. Although adoptive T-cell therapy has been successfully used in hematopoietic stem cell transplant recipients, its extension to the SOT setting poses a considerable challenge because of the inhibitory effects of immunosuppressive drugs on the virus-specific T-cell response in vivo and the perceived risk of graft rejection. Methods In this prospective study, 22 SOT recipients (13 renal and 8 lung and 1 heart transplants) with recurrent or ganciclovir-resistant CMV infection were recruited, and 13 of them were treated with in vitro-expanded autologous CMV-specific T cells. These patients were monitored for safety, clinical symptoms, and immune reconstitution. Results Autologous CMV-specific T-cell manufacture was attempted for 21 patients, and was successful in 20. The use of this adoptive immunotherapy was associated with no therapy-related serious adverse events. Eleven (84%) of the 13 treated patients showed improvement in symptoms, including complete resolution or reduction in DNAemia and CMV-associated end-organ disease and/or the cessation or reduced use of antiviral drugs. Furthermore, four of these patients showed coincident increased frequency of CMV-specific T cells in peripheral blood after completion of T-cell therapy. Conclusions The data presented here demonstrate for the first time the clinical safety of CMV-specific adoptive T-cell therapy and its potential therapeutic benefit for SOT recipients with recurrent and/or drug-resistant CMV infection or disease. Clinical Trials Registration ACTRN12613000981729.

BACKGROUNDThe recent failure of checkpoint-blockade therapies for glioblastoma multiforme (GBM) in late-phase clinical trials has directed interest toward adoptive cellular therapies (ACTs). In this open-label, first-in-human trial, we have assessed the safety and therapeutic potential of cytomegalovirus-specific (CMV-specific) ACT in an adjuvant setting for patients with primary GBM, with an ultimate goal to prevent or delay recurrence and prolong overall survival.METHODSTwenty-eight patients with primary GBM were recruited to this prospective study, 25 of whom were treated with in vitro-expanded autologous CMV-specific T cells. Participants were monitored for safety, progression-free survival, overall survival (OS), and immune reconstitution.RESULTSNo participants showed evidence of ACT-related toxicities. Of 25 evaluable participants, 10 were alive at the completion of follow-up, while 5 were disease free. Reconstitution of CMV-specific T cell immunity was evident and CMV-specific ACT may trigger a bystander effect leading to additional T cell responses to nonviral tumor-associated antigens through epitope spreading. Long-term follow-up of participants treated before recurrence showed significantly improved OS when compared with those who progressed before ACT (median 23 months, range 7-65 vs. median 14 months, range 5-19; P = 0.018). Gene expression analysis of the ACT products indicated that a favorable T cell gene signature was associated with improved long-term survival.CONCLUSIONData presented in this study demonstrate that CMV-specific ACT can be safely used as an adjuvant therapy for primary GBM and, if offered before recurrence, this therapy may improve OS of GBM patients.TRIAL REGISTRATIONanzctr.org.au: ACTRN12615000656538.FUNDINGPhilanthropic funding and the National Health and Medical Research Council (Australia).