Generation of human T cell clones

Cancer Therapy With TCR-Engineered T Cells: Current Strategies, Challenges, and Prospects

To redirect T cells against tumor cells, T cells can be engineered ex vivo to express cancer-antigen specific T cell receptors (TCRs), generating products known as TCR-engineered T cells (TCR T). Unlike chimeric antigen receptors (CARs), TCRs recognize HLA-presented peptides derived from proteins of all cellular compartments. The use of TCR T cells for adoptive cellular therapies (ACT) has gained increased attention, especially as efforts to treat solid cancers with ACTs have intensified. In this review, we describe the differing mechanisms of T cell antigen recognition and signal transduction mediated through CARs and TCRs. We describe the classes of cancer antigens recognized by current TCR T therapies and discuss both classical and emerging pre-clinical strategies for antigen-specific TCR discovery, enhancement, and validation. Finally, we review the current landscape of clinical trials for TCR T therapy and discuss what these current results indicate for the development of future engineered TCR approaches.

An efficient method to identify virus-specific TCRs for TCR-T cell immunotherapy against virus-associated malignancies

Adoptive transfer of T cells genetically engineered with a T cell receptor (TCR) is a promising cancer treatment modality that requires the identification of TCRs with good characteristics. Most T cell cloning methods involve a stringent singularization process, which necessitates either tedious hands-on operations or high cost. We present an efficient and nonstringent cloning approach based on existing techniques. We hypothesize that after elimination of most nonspecific T cells, a clonotype with high quality could outcompete other clonotypes and finally form a predominant population. This TCR identification method can be used to clone virus-specific TCRs efficiently from cancer patients and is easily adoptable by any laboratory.

Antibiotic-associated dysbiosis affects the ability of the gut microbiota to control intestinal inflammation upon fecal microbiota transplantation in experimental colitis models

BACKGROUND

The gut microbiota plays a central role in host physiology and in several pathological mechanisms in humans. Antibiotics compromise the composition and functions of the gut microbiota inducing long-lasting detrimental effects on the host. Recent studies suggest that the efficacy of different clinical therapies depends on the action of the gut microbiota. Here, we investigated how different antibiotic treatments affect the ability of the gut microbiota to control intestinal inflammation upon fecal microbiota transplantation in an experimental colitis model and in ex vivo experiments with human intestinal biopsies.

RESULTS

Murine fecal donors were pre-treated with different antibiotics, i.e., vancomycin, streptomycin, and metronidazole before FMT administration to colitic animals. The analysis of the gut microbiome, fecal metabolome, and the immunophenotyping of colonic lamina propria immune cells revealed that antibiotic pre-treatment significantly influences the capability of the microbiota to control intestinal inflammation. Streptomycin and vancomycin-treated microbiota failed to control intestinal inflammation and were characterized by the blooming of pathobionts previously associated with IBD as well as with metabolites related to the presence of oxidative stress and metabolism of simple sugars. On the contrary, the metronidazole-treated microbiota retained its ability to control inflammation co-occurring with the enrichment of Lactobacillus and of innate immune responses involving iNKT cells. Furthermore, ex vivo cultures of human intestinal lamina propria mononuclear cells and iNKT cell clones from IBD patients with vancomycin pre-treated sterile fecal water showed a Th1/Th17 skewing in CD4⁺ T-cell populations; metronidazole, on the other hand, induced the polarization of iNKT cells toward the production of IL10.

CONCLUSIONS

Diverse antibiotic regimens affect the ability of the gut microbiota to control intestinal inflammation in experimental colitis by altering the microbial community structure and microbiota-derived metabolites. Video Abstract.

Comparative Analysis of T-Cell Responses to Aquaporin-4 and Myelin Oligodendrocyte Glycoprotein in Inflammatory Demyelinating Central Nervous System Diseases

Autoantibodies against aquaporin-4 (AQP4-Ab) and myelin oligodendrocyte glycoprotein (MOG-Ab) are associated with rare central nervous system inflammatory demyelinating diseases like neuromyelitis optica spectrum disorders (NMOSD). Previous studies have shown that not only antibodies, but also autoreactive T-cell responses against AQP4 are present in NMOSD. However, no study has yet analyzed the presence of MOG reactive T-cells in patients with MOG antibodies. Therefore, we compared AQP4 and MOG specific peripheral T-cell response in individuals with AQP4-Ab (n = 8), MOG-Ab (n = 10), multiple sclerosis (MS, n = 8), and healthy controls (HC, n = 14). Peripheral blood mononuclear cell cultures were stimulated with eight AQP4 and nine MOG peptides selected from previous studies and a tetanus toxoid peptide mix as a positive control. Antigen-specific T-cell responses were assessed using the carboxyfluorescein diacetate succinimidyl ester proliferation assay and the detection of granulocyte macrophage colony-stimulating factor (GM-CSF), interferon (IFN)-ɤ and interleukin (IL)-4, IL-6, and IL-17A in cell culture supernatants. Additionally, human leukocyte antigen (HLA)-DQ and HLA-DR genotyping of all participants was performed. We classified a T-cell response as positive if proliferation (measured by a cell division index ≥3) was confirmed by the secretion of at least one cytokine. Reactivity against AQP4 peptides was observed in many groups, but the T-cell response against AQP4 p156-170 was present only in patients with AQP4-Ab (4/8, 50%) and absent in patients with MOG-Ab, MS and HC (corrected p = 0.02). This AQP4 p156-170 peptide specific T-cell response was significantly increased in participants with AQP4-Ab compared to those without [Odds ratio (OR) = 59.00, 95% confidence interval-CI 2.70–1,290.86]. Moreover, T-cell responses against at least one AQP4 peptide were also more frequent in participants with AQP4-Ab (OR = 11.45, 95% CI 1.24–106.05). We did not observe any significant differences for the other AQP4 peptides or any MOG peptide. AQP4-Ab were associated with HLA DQB1^*02 (OR = 5.71, 95% CI 1.09–30.07), DRB1^*01 (OR = 9.33, 95% CI 1.50–58.02) and DRB1^*03 (OR = 6.75, 95% CI = 1.19–38.41). Furthermore, HLA DRB1^*01 was also associated with the presence of AQP4 p156-170 reactive T-cells (OR = 31.67, 95% CI 1.30–772.98). To summarize, our findings suggest a role of AQP4-specific, but not MOG-specific T-cells, in NMOSD.

Preliminary In Vitro Effects of CD8+ T Lymphocyte Specific for the CD20 Alternative Splicing D393-CD20 Peptide Expressed on Burkitt Lymphoma Cells

The effective discovery of clinically relevant tumor antigens holds a fundamental role for the development of new diagnostic tools and anticancer immunotherapies. D393-CD20 mRNA is absent from normal resting B cells but present in various malignant or transformed B cells. CD8+T lymphocytes play a central role in immunity to cancer. In this study, we want use from T CD8+ against D393-CD20 for effect in RAMOS cell line. After isolation and expanding of specific TCD8 + Lymphocyte against D393-CD20 antigen, for examining the effect of specialized T lymphocyte clone of D393-CD20 antigen on RAMOS cell line, we co-cultured them together, and the rate of apoptosis were examined by flow cytometry and cytotoxicity techniques by using MTT technique. We observed that specialized TCD8+ lymphocyte of D393-CD20 antigen can induce apoptosis in malignant B-lymphocytes, and this antigen can be a proper target for immunotherapy.

Testing the Impact of Protease Inhibitors in Antigen Presentation Assays

The major histocompatibility complex (MHC) class I restricted pathway of antigen processing allows the presentation of intracellular antigens to cytotoxic T lymphocytes. The proteasome is the main protease in the cytoplasm and the nucleus, which is responsible for the generation of most peptide ligands of MHC-I molecules. Peptides produced by the proteasome can be further trimmed or destroyed by numerous cytosolic or endoplasmic reticulum (ER) luminal proteases. Small molecule inhibitors are useful tools for probing the role of proteases in MHC class I antigen processing. Here, we describe different methods to test the impact of protease inhibitors in antigen presentation assays.

Genetic abrogation of immune checkpoints in antigen-specific cytotoxic T-lymphocyte as a potential alternative to blockade immunotherapy

T cell function can be compromised during chronic infections or through continuous exposure to tumor antigens by the action of immune checkpoint receptors, such as programmed cell death protein 1 (PD-1). Systemic administration of blocking antibodies against the PD-1 pathway can restore T cell function, and has been approved for the treatment of several malignancies, although there is a risk of adverse immune-related side-effects. We have developed a method for generating gene knockouts in human antigen (Ag)-specific cytotoxic T-Lymphocyte (CTLs) using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) genome editing. Using this method, we generated several transduced CD4⁺ or CD8⁺ antigen-specific polyclonal CTL lines and clones, and validated gene modifications of the PD-1 gene. We compared these T-cell lines and clones with control groups in the presence of programmed death-ligand 1 (PD-L1) and observed improved effector functions in the PD1-disrupted cell group. Overall, we have developed a versatile tool for functional genomics in human antigen-specific CTL studies. Furthermore, we provide an alternative strategy for current cell-based immunotherapy that will minimize the side effects caused by antibody blockade therapy.

Adoptive T-cell therapy for Leukemia

Allogeneic stem cell transplantation (alloSCT) is the most robust form of adoptive cellular therapy (ACT) and has been tremendously effective in the treatment of leukemia. It is one of the original forms of cancer immunotherapy and illustrates that lymphocytes can specifically recognize and eliminate aberrant, malignant cells. However, because of the high morbidity and mortality that is associated with alloSCT including graft-versus-host disease (GvHD), refining the anti-leukemia immunity of alloSCT to target distinct antigens that mediate the graft-versus-leukemia (GvL) effect could transform our approach to treating leukemia, and possibly other hematologic malignancies. Over the past few decades, many leukemia antigens have been discovered that can separate malignant cells from normal host cells and render them vulnerable targets. In concert, the field of T-cell engineering has matured to enable transfer of ectopic high-affinity antigen receptors into host or donor cells with greater efficiency and potency. Many preclinical studies have demonstrated that engineered and conventional T-cells can mediate lysis and eradication of leukemia via one or more leukemia antigen targets. This evidence now serves as a foundation for clinical trials that aim to cure leukemia using T-cells. The recent clinical success of anti-CD19 chimeric antigen receptor (CAR) cells for treating patients with acute lymphoblastic leukemia and chronic lymphocytic leukemia displays the potential of this new therapeutic modality. In this review, we discuss some of the most promising leukemia antigens and the novel strategies that have been implemented for adoptive cellular immunotherapy of lymphoid and myeloid leukemias. It is important to summarize the data for ACT of leukemia for physicians in-training and in practice and for investigators who work in this and related fields as there are recent discoveries already being translated to the patient setting and numerous accruing clinical trials. We primarily focus on ACT that has been used in the clinical setting or that is currently undergoing preclinical testing with a foreseeable clinical endpoint.

Using protease inhibitors in antigen presentation assays

The major histocompatibility complex (MHC) class I restricted pathway of antigen processing allows the presentation of intracellular antigens to cytotoxic T lymphocytes. The proteasome is the main protease in the cytoplasm and the nucleus, which is responsible for the generation of most peptide ligands of MHC-I molecules. Peptides produced by the proteasome can be further trimmed or destroyed by numerous cytosolic or endoplasmic reticulum (ER) lumenal proteases. Small molecule inhibitors are useful tools for probing the role of proteases in MHC class I antigen processing. Here, we describe different methods to test the impact of protease inhibitors in antigen presentation assays.

Autoreactive T Cells in Human Smokers is Predictive of Clinical Outcome

Cross-sectional studies have suggested a role for activation of adaptive immunity in smokers with emphysema, but the clinical application of these findings has not been explored. Here we examined the utility of detecting autoreactive T cells as a screening tool for emphysema in an at-risk population of smokers. We followed 156 former and current (ever)-smokers for 2 years to assess whether peripheral blood CD4 T cell cytokine responses to lung elastin fragments (EFs) could discriminate between those with and without emphysema, and to evaluate the relevance of autoreactive T cells to predict changes during follow-up in lung physiological parameters. Volunteers underwent baseline complete phenotypic assessment with pulmonary function tests, quantitative chest CT, yearly 6-min walk distance (6MWD) testing, and annual measurement of CD4 T cell cytokine responses to EFs. The areas under the receiver operating characteristic curve to predict emphysema for interferon gamma (IFN-γ), and interleukin 6 (IL-6) responses to EFs were 0.81 (95% CI of 0.74-0.88) and 0.79 (95% CI of 0.72-0.86) respectively. We developed a dual cytokine enzyme-linked immunocell spot assay, the γ-6 Spot, using CD4 T cell IFN-γ and IL-6 responses and found that it discriminated emphysema with 90% sensitivity. After adjusting for potential confounders, the presence of autoreactive T cells was predictive of a decrease in 6MWD over 2 years (decline in 6MWD, -19 m per fold change in IFN-γ; P = 0.026, and -26 m per fold change in IL-6; P = 0.003). In support of the human association studies, we cloned CD4 T cells with characteristic T helper (Th)1 and Th17 responses to EFs in the peripheral blood of ever-smokers with emphysema, confirming antigenicity of lung elastin in this population. These findings collectively suggest that the EF-specific autoreactive CD4 T cell assay, γ-6 Spot, could provide a non-invasive diagnostic tool with potential application to large-scale screening to discriminate emphysema in ever-smokers, and predict early relevant physiological outcomes in those at risk.