scholarly journals IMMU-02. NEOANTIGENS ARISING FROM ALTERNATIVE SPLICING EVENTS MAY BE TARGETED BY TUMOR INFILTRATING LYMPHOCYTES IN GLIOBLASTOMAS

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi118-vi119
Author(s):  
Alexander Lee ◽  
Yang Pan ◽  
Aaron Mochizuki ◽  
Mildred Galvez ◽  
Frances Chow ◽  
...  

Abstract INTRODUCTION Alternative splicing, the cellular process that converts premature mRNA to mature mRNA and allows for single genes to produce multiple protein products, is frequently dysregulated in many cancers, including glioblastoma. However, along with non-synonymous mutations in the DNA, altered splicing mechanisms in cancers may produce novel antigens (so-called neoantigens) that distinguish cancer cells from healthy cells and can thus be targeted by the immune system. METHODS We developed a new computation pipeline (IRIS – Isoform peptides from RNA splicing for Immunotherapy targets Screening) that took bulk RNA-sequencing data from 23 glioblastoma patient tumor samples and predicted neoantigens that may arise from alternative splicing events. We prioritized predicted neoantigens that arose in HLA*A02:01 and HLA*A03:01 patients and selected 8 potential neoantigens to generate peptide:MHC Class 1 dextramers. We tested PBMCs and/or ex vivo expanded tumor infiltrating lymphocytes (TIL) from 6 of our glioblastoma patients against these dextramers, sorted for any neoantigen-reactive T cells, and performed single-cell RNAsequencing on the sorted population to determine the TCR sequence. RESULTS Among the 8 predicted neoantigens tested, 7 of the neoantigens were recognized by at least 1 patient’s T cells. 1 HLA*A03:01 epitope was recognized in 3 of the 4 HLA*A03:01 patients tested and this epitope was highly positive in an expanded TIL population, representing 1.7% of all CD3+ CD8+ cells. When we sorted for those neoantigen reactive T cells from the expanded TIL population and performed single-cell RNAsequencing, we found 325 unique T cell clonotypes, but the top 10 clonotypes represented 83.6% of all TCR clonotypes. The most frequent TCR clonotype represented 39.1% of the repertoire and suggests that clonal expansion of a select few TCR clones occurred within the tumor. CONCLUSIONS In total, our data indicates that neoantigens arising from alternative splicing events may represent a potential target for immunotherapy in glioblastoma.

2020 ◽  
Author(s):  
Shang Liu ◽  
Biaofeng Zhou ◽  
Liang Wu ◽  
Yan Sun ◽  
Jie Chen ◽  
...  

AbstractRecent advances in single-cell RNA sequencing (scRNA-seq), enriched the knowledge of the heterogeneity of the tumor-infiltrating lymphocytes (TIL) for understanding the mechanisms of cancer initiation and progression. However, alternative splicing (AS), as one of the important regulatory factors of heterogeneity, has been poorly investigated. Here, we proposed a computational tool, DESJ-detection, which could fast and accurately detect the differentially expressed splicing junction (DESJ) between cell groups at single-cell level. We analyzed 5,063 T cells of hepatocellular carcinoma (HCC) and identified 1,176 DESJs across 11 T cell subtypes. Cell subtypes with a similar function clustered closer rather than the lineage at the AS level. Meanwhile, we identified two novel cell states, pre-exhaustion and pre-activation with the marker isoform CD103-201 and ARHGAP15-205. In summary, we presented a comprehensive investigation of alternative splicing differences, which provided novel insights for heterogeneity of T cells and can be applied in other full-length scRNA-seq datasets.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A822-A822
Author(s):  
Sri Krishna ◽  
Frank Lowery ◽  
Amy Copeland ◽  
Stephanie Goff ◽  
Grégoire Altan-Bonnet ◽  
...  

BackgroundAdoptive T cell therapy (ACT) utilizing ex vivo-expanded autologous tumor infiltrating lymphocytes (TILs) can result in complete regression of human cancers.1 Successful immunotherapy is influenced by several tumor-intrinsic factors.2 3 Recently, T cell-intrinsic factors have been associated with immunotherapy response in murine and human studies.4 5 Analyses of tumor-reactive TILs have concluded that anti-tumor neoantigen-specific TILs are enriched in subsets defined by the expression of PD-1 or CD39.6 7 Thus, there is a lack of consensus regarding the tumor-reactive TIL subset that is directly responsible for successful immunotherapies such as ICB and ACT. In this study, we attempted to define the fitness landscape of TIL-enriched infusion products to specifically understand its phenotypic impact on human immunotherapy responses.MethodsWe compared the phenotypic differences that could distinguish bulk ACT infusion products (I.P.) administered to patients who had complete response to therapy (complete responders, CRs, N = 24) from those whose disease progressed following ACT (non-responders, NRs, N = 30) by high dimensional single cell protein and RNA analysis of the I.P. We further analyzed the phenotypic states of anti-tumor neoantigen specific TILs from patient I.P (N = 26) by flow cytometry and single cell transcriptomics.ResultsWe identified two CD8+ TIL populations associated with clinical outcomes: a memory-progenitor CD39-negative stem-like TIL (CD39-CD69-) in the I.P. associated with complete cancer regression (overall survival, P < 0.0001, HR = 0.217, 95% CI 0.101 to 0.463) and TIL persistence, and a terminally differentiated CD39-positive TIL (CD39+CD69+) population associated with poor TIL persistence post-treatment. Although the majority (>65%) of neoantigen-reactive TILs in both responders and non-responders to ACT were found in the differentiated CD39+ state, CR infusion products also contained a pool of CD39- stem-like neoantigen-specific TILs (median = 8.8%) that was lacking in NR infusion products (median = 23.6%, P = 1.86 x 10-5). Tumor-reactive stem-like T cells were capable of self-renewal, expansion, and persistence, and mediated superior anti-tumor response in vivo.ConclusionsOur results support the hypothesis that responders to ACT received infusion products containing a pool of stem-like neoantigen-specific TILs that are able to undergo prolific expansion, give rise to differentiated subsets, and mediate long-term tumor control and T cell persistence, in line with recent murine ICB studies mediated by TCF+ progenitor T cells.4 5 Our data also suggest that TIL subsets mediating ACT-response (stem-like CD39-) might be distinct from TIL subsets enriched for anti-tumor-reactivity (terminally differentiated CD39+) in human TIL.6 7AcknowledgementsWe thank Don White for curating the melanoma patient cohort, and J. Panopoulos (Flowjo) for helpful discussions on high-dimensional analysis, and NCI Surgery Branch members for helpful insights and suggestions. S. Krishna acknowledges funding support from NCI Director’s Innovation Award from the National Cancer Institute.Trial RegistrationNAEthics ApprovalThe study was approved by NCI’s IRB ethics board.ReferencesGoff SL, et al. Randomized, prospective evaluation comparing intensity of lymphodepletion before adoptive transfer of tumor-infiltrating lymphocytes for patients with metastatic melanoma. J Clin Oncol 2016;34:2389–2397.Snyder A, et al. Genetic basis for clinical response to CTLA-4 blockade in melanoma. N Engl J Med 2014;371:2189–2199.McGranahan N, et al. Clonal neoantigens elicit T cell immunoreactivity and sensitivity to immune checkpoint blockade. Science 2016;351:1463–1469.Sade-Feldman M, et al. Defining T cell states associated with response to checkpoint immunotherapy in melanoma. Cell 2019;176:404.Miller BC, et al. Subsets of exhausted CD8 T cells differentially mediate tumor control and respond to checkpoint blockade. Nat. Immunol 2019;20:326–336.Simoni Y, et al. Bystander CD8 T cells are abundant and phenotypically distinct in human tumour infiltrates. Nature 2018;557:575–579.Gros A, et al. PD-1 identifies the patient-specific CD8+ tumor-reactive repertoire infiltrating human tumors. J Clin Invest 2014;124:2246–2259.


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A538-A538
Author(s):  
Sean Judge ◽  
Morgan Darrow ◽  
Steven Thorpe ◽  
Alicia Gingrich ◽  
Edmond O’Donnell ◽  
...  

BackgroundAlthough the presence and activity of tumor infiltrating lymphocytes (TILs) have been shown to be important factors for survival and response to immunotherapy for multiple cancer types, the benefits of immunotherapy in soft tissue sarcomas (STS) have been limited, and novel approaches are needed. In this study, we sought to characterize the phenotype and function of tumor infiltrating natural killer (NK) and T cells in STS patients and to evaluate clinically relevant strategies to augment TIL function.MethodsUsing both prospectively collected blood and tumor tissue from STS patients undergoing surgical resection (n = 21) and archived specimens (n = 45), we performed flow cytometry and immunohistochemistry to evaluate the extent of peripheral and intratumoral CD3-CD56+ NK and CD8+ T cell phenotype and function as predictors of outcome. We also analyzed TCGA data and the peripheral blood of dogs with spontaneous osteosarcoma receiving inhaled IL-15 on a clinical trial to evaluate the association of CD3-NKp46+ NK and CD8+ T cell activation as well as TIGIT upregulation with outcome. Finally, we stimulated patient PBMCs and TILs ex vivo with IL-15 and a novel human anti-TIGIT antibody to assess the impact of combination therapy on NK and T cell phenotype and function. Parametric and non-parametric statistical tests were used where appropriate. Univariate and multivariate survival analyses were performed by Cox proportional hazards models.ResultsCompared to peripheral expression, intratumoral NK and T cells showed an activated and exhausted phenotype by CD69 and TIGIT, respectively. Ex vivo TIL stimulation with IL-15 further increased markers of activation and function including CD69, Ki67, IFNg, and granzyme B, while increasing expression of exhaustion marker TIGIT. Analysis of a retrospective STS cohort and TCGA STS gene expression confirmed the association of TILs with improved prognosis. Dogs with metastatic osteosarcoma receiving inhaled IL-15 exhibited upregulation of activation markers and TIGIT. In vitro, IL-15 and TIGIT blockade of both peripheral and intratumoral NK cells increased cytotoxicity against sarcoma cell lines and increased expression of degranulation marker CD107a compared to IL-15 alone.ConclusionsTILs are associated with improved survival in STS, and tumor infiltrating NK and T cells show features of both increased activation and increased exhaustion. Tumor-infiltrating NK and T cells respond to IL-15 stimulation, but simultaneously further upregulate TIGIT with the combination of IL-15 and TIGIT blockade showing greatest cytotoxic effects. Overall, our data suggest that the combination of IL-15 and TIGIT blockade is a promising clinical strategy in STS.Ethics ApprovalAll experiments involving human and canine patients were approved by the respective Institutional Review Boards at the University of California, Davis, Schools of Medicine (Protocol #218204-9) and Veterinary Medicine (IACUC #20179).


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A71-A71
Author(s):  
Yukari Kobayashi ◽  
Koji Nagaoka ◽  
Kaori Kubo ◽  
Toshikazu Nishie ◽  
Sachiko Okamoto ◽  
...  

BackgroundT-cells that target tumor neoantigens arising from cancer mutations are the primary mediators of cancer immunotherapies. Identifying neoantigens and T-cells that recognize them is essential for T-cell-based immunotherapy. However, neoantigen-reactive Tumor-infiltrating lymphocytes (TILs) are highly differentiated or exhausted with a limited proliferative capacity; it is challenging to expand them for a sufficient number to probe their specificity. Therefore, we developed a novel cloning and expression system to examine TCRs discovered by single-cell sequencing of TILs for their neoantigen-specificity.MethodsTILs of lung cancer and sarcoma were analyzed. Surgically removed tumors were divided into several pieces. They were enzymatically digested to prepare fresh tumor digest (FTD) and cryopreserved. They were used to generate TIL cultures and perform WES and RNA-Seq to identify tumor-specific mutations. MHCflurry was used to predict the binding affinity of potential epitopes arising from these mutations to HLA class I. Peptides that were predicted to bind to patients‘ own MHC class I molecules strongly were then synthesized. Single TILs isolated with the ICELL8® cx system (Takara Bio) were dispensed into a nanowell TCR chip containing preprinted barcodes. Barcoded cDNAs were PCR-amplified in-chip, pooled off-chip, and used as a template in the TCR-specific PCR or for the whole transcriptome library generation of 5’ ends of all transcripts. Based on single-cell transcriptome data and TCR profiles of TILs, we predict and prioritize neoantigen-specific TCRs and cloned them into siTCR® retrovirus vectors. These TCRs were transduced into SUP-T1-based reporter cells in which ZsGreen fluorescent protein expression is controlled by AP-1 and NFAT binding sites. TCR-expressing reporter cells were cocultured with patient autologous APCs pulsed with a pool of candidate neoantigen peptides. ZsGreen expression indicates that TCRs match their cognate neoantigens.ResultsIn a lung cancer patient, we set up 18 TIL cultures and obtained 12 TILs. TILs were cocultured with FTD; IFN-γ production was measured by ELISA to evaluate their reactivity to the autologous tumor. NGS identified 197 somatic mutations, 4 fusion genes, and 8 highly expressed cancer-testis antigens. Among them, 339 candidate peptides were synthesized and screened. In addition, we cloned 3 pairs of TCRαβ chains from most expanded TIL cultures and 4 TCRs from ex vivo TILs with exhausted phenotype. Two reporter cells that express TCRs from exhausted TILs responded to the same neoantigen peptide.ConclusionsGenerating TCR expressing cell lines facilitated the identifying neoantigens and their cognate TCR sequences from patients.Ethics ApprovalG3545


Author(s):  
Cornelis J M Melief

Abstract During the last two decades two main schools of modern immunotherapy have come to the forefront. The chimeric anti-CD20 antibody rituximab that was introduced for the treatment of refractory follicular lymphoma in 1998 was one of the first examples of the school of passive immunotherapy. Subsequently major and ever more costly efforts were spent on the development of blockbuster monotherapies including other monoclonal but also bispecific antibodies of highly defined specificity and subclass, antibody-drug-conjugates (ADCs), as well as ex vivo expanded tumor infiltrating lymphocytes, CAR-transduced T cells, and TCR-transduced T cells. On the other hand there is the school that works towards active induction of patient B- or T-cell immunity against antigens of choice, or active tolerance against pathogenic allergens, auto-antigens or allo-antigens. Stradled in between these two approaches is treatment with blockers of T cell checkpoint control, which releases the brakes of T cells that have already responded to antigen. Extensive and detailed insight into the cellular and molecular interactions that regulate specific immune responses is indispensable in order to be able to optimize efficacy and rule out treatment related toxicity. This applies to all types of immunotherapy. Our knowledge of the checks and balances in the immune system is still increasing at an unprecedented pace, fostering ever more effective and specific (combination) immunotherapies and offering a rich harvest of innovative immunotherapies in the years ahead.


Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1260
Author(s):  
Sofia Papanikolaou ◽  
George K. Bertsias ◽  
Christoforos Nikolaou

In addition to increasing the complexity of the transcriptional output, alternative RNA splicing can lead to the reduction of mRNA translation or the production of non-functional or malfunctional proteins, thus representing a vital component of the gene regulation process. Herein, we set out to detect and characterize alternative splicing events that occur in whole-blood samples of patients with Systemic Lupus Erythematosus (SLE) as compared to healthy counterparts. Through the implementation of a computational pipeline on published RNA-sequencing data, we identified extensive changes in the transcription dynamics affecting a large number of genes. We found a predominance of intron retention events, with the majority introducing premature stop codons, suggestive of gene repression, in both inactive and active SLE patient samples. Alternative splicing affected a distinct set of genes from the ones detected as differentially expressed in the same comparisons, while alternatively spliced genes tended to reside in genome areas associated with increased gene co-expression. Functional analysis of genes affected by alternative splicing pointed towards particular functions related to metabolism and histone acetylation as of potential interest. Together, our findings underline the importance of incorporating alternative splicing analyses in the context of molecular characterization of complex diseases such as SLE.


Author(s):  
Yannick Simoni ◽  
Shamin Li ◽  
Summer Zhuang ◽  
Antja Heit ◽  
Si-Lin Koo ◽  
...  

AbstractTumor-specific T cells likely underpin effective immune checkpoint-blockade therapies. Yet, most studies focus on Treg cells and CD8+ tumor-infiltrating lymphocytes (TILs). Here we study CD4+ TILs in human lung and colorectal cancers and observe that non-Treg CD4+ TILs average more than 70% of total CD4+ TILs in both cancer types. Leveraging high dimensional analyses including mass cytometry and single-cell sequencing, we reveal that CD4+ TILs are heterogeneous at both gene and protein levels, within each tumor and across patients. Consistently, we find different subsets of CD4+ TILs showing characteristics of effectors, tissue resident memory (Trm) or exhausted cells (expressing PD-1, CTLA-4 and CD39). In both cancer types, the frequencies of CD39− non-Treg CD4+ TILs strongly correlate with frequencies of CD39− CD8+ TILs, which we and others have previously shown to be enriched for cells specific for cancer-unrelated antigens (bystanders). Ex-vivo, we demonstrate that CD39− CD4+ TILs can be specific for cancer unrelated antigens, such as HCMV epitopes. Overall, our findings highlight that CD4+ TILs cells are not necessarily tumor-specific and suggest measuring CD39 expression as a straightforward way to quantify or isolate bystander CD4+ T cells.Graphical abstract


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 6055-6055
Author(s):  
Hannah Knochelmann ◽  
Joshua Dean Horton ◽  
Megan Meek ◽  
Carsten Krieg ◽  
Cynthia Dawn Timmers ◽  
...  

6055 Background: PD-1 inhibition therapy has revolutionized clinical medicine as it can mediate durable responses in a small cohort of patients. Yet, it remains incompletely understood why these patients respond. To address this question, we studied patients with oral cavity squamous cell carcinoma (OCSCC) to elucidate immune phenotypes associated with response to nivolumab. Methods: We defined the immune profile from the blood and tumor of patients on neoadjuvant nivolumab. We tested if tumor-infiltrating lymphocytes (TIL) could be preferentially expanded ex vivo from nivolumab-responsive patients versus those who were either non-responsive or had never received nivolumab. During the course of therapy, we comprehensively profiled a number of surface markers on patients’ T cells to define their activation status, cytotoxic capacity and memory phenotype. Moreover, the immune profile of the peripheral blood was assessed pre- and post-nivolumab using high dimensional mass cytometry. Results: Regardless of PD-1 therapy, TIL were successfully expanded from 11 of the 12 patients. TIL were comprised of both CD4+ and CD8+ T cells. Additional investigation revealed that the frequency of CD4+ T cells and effector memory T cells in TIL correlated with disease progression (CD4: p = 0.04, r = 0.74, effector memory: p = 0.046, r = 0.74). TILs from responders expressed higher CD26 (p = 0.007, r = -0.88) and Tim3 (p = 0.045, r = -0.74) while PD-1, Lag3, and Ox40 were not differentially expressed based on response. Spearman correlation and Mann Whitney U test were used to assess phenotypic differences. Conclusions: We demonstrate, for the first time, that TIL can be reliably expanded from OCSCC patients on neoadjuvant nivolumab. Moreover, individuals who were responsive to PD-1 blockade had TIL expressing high levels of CD26 and Tim3. Future studies will explore if these markers are predictive of responses and if they contribute to treatment outcome.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David S. Fischer ◽  
Meshal Ansari ◽  
Karolin I. Wagner ◽  
Sebastian Jarosch ◽  
Yiqi Huang ◽  
...  

AbstractThe in vivo phenotypic profile of T cells reactive to severe acute respiratory syndrome (SARS)-CoV-2 antigens remains poorly understood. Conventional methods to detect antigen-reactive T cells require in vitro antigenic re-stimulation or highly individualized peptide-human leukocyte antigen (pHLA) multimers. Here, we use single-cell RNA sequencing to identify and profile SARS-CoV-2-reactive T cells from Coronavirus Disease 2019 (COVID-19) patients. To do so, we induce transcriptional shifts by antigenic stimulation in vitro and take advantage of natural T cell receptor (TCR) sequences of clonally expanded T cells as barcodes for ‘reverse phenotyping’. This allows identification of SARS-CoV-2-reactive TCRs and reveals phenotypic effects introduced by antigen-specific stimulation. We characterize transcriptional signatures of currently and previously activated SARS-CoV-2-reactive T cells, and show correspondence with phenotypes of T cells from the respiratory tract of patients with severe disease in the presence or absence of virus in independent cohorts. Reverse phenotyping is a powerful tool to provide an integrated insight into cellular states of SARS-CoV-2-reactive T cells across tissues and activation states.


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