T-cell receptor affinity in the age of cancer immunotherapy

Targeting SHP1 and SHP2 to suppress tumors and enhance immunosurveillance

The nonreceptor tyrosine phosphatases (PTPS) SHP1 and SHP2 have crucial roles in dephosphorylating an array of substrates involved in pathways comprising receptor tyrosine kinases (RTKs) and immune receptors. This regulation maintains a delicate balance between the activation and inhibition of signal transduction, ensuring appropriate biological outcomes. In this review, we summarize research focused on elucidating the functions of SHP1 and SHP2 in hematopoiesis, immune regulation, and tumor biology, emphasizing recent findings related to cancer-driven immune evasion. Furthermore, we highlight the significant effects of SHP1 and SHP2 inhibitors in enhancing cancer treatment, specifically through the facilitation of chemotherapy and augmentation of immune activation.

SLAMF7 (CD319) on activated CD8+ T cells transduces environmental cues to initiate cytotoxic effector cell responses

CD8+ T-cell responses are meticulously orchestrated processes regulated by intercellular receptor:ligand interactions. These interactions critically control the dynamics of CD8+ T-cell populations that is crucial to overcome threats such as viral infections or cancer. Yet, the mechanisms governing these dynamics remain incompletely elucidated. Here, we identified a hitherto unknown T-cell referred function of the self-ligating surface receptor SLAMF7 (CD319) on CD8+ T cells during initiation of cytotoxic T-cell responses. According to its cytotoxicity related expression on T effector cells, we found that CD8+ T cells could utilize SLAMF7 to transduce environmental cues into cellular interactions and information exchange. Indeed, SLAMF7 facilitated a dose-dependent formation of stable homotypic contacts that ultimately resulted in stable cell-contacts, quorum populations and commitment to expansion and differentiation. Using pull-down assays and network analyses, we identified novel SLAMF7-binding intracellular signaling molecules including the CRK, CRKL, and Nck adaptors, which are involved in T-cell contact formation and may mediate SLAMF7 functions in sensing and adhesion. Hence, providing SLAMF7 signals during antigen recognition of CD8+ T cells enhanced their overall magnitude, particularly in responses towards low-affinity antigens, resulting in a significant boost in their proliferation and cytotoxic capacity. Overall, we have identified and characterized a potent initiator of the cytotoxic T lymphocyte response program and revealed advanced mechanisms to improve CD8+ T-cell response decisions against weak viral or tumor-associated antigens, thereby strengthening our defense against such adversaries.

Analysis of protein-protein and protein-membrane interactions by isotope-edited infrared spectroscopy

The objective of this work is to highlight the power of isotope-edited Fourier transform infrared (FTIR) spectroscopy in resolving important problems encountered in biochemistry, biophysics, and biomedical research, focusing on protein-protein and protein membrane interactions that play key roles in practically all life processes. An overview of the effects of isotope substitutions in (bio)molecules on spectral frequencies and intensities is given. Data are presented demonstrating how isotope-labeled proteins and/or lipids can be used to elucidate enzymatic mechanisms, the mode of membrane binding of peripheral proteins, regulation of membrane protein function, protein aggregation, and local and global structural changes in proteins during functional transitions. The use of polarized attenuated total reflection FTIR spectroscopy to identify the spatial orientation and the secondary structure of a membrane-bound interfacial enzyme and the mode of lipid hydrolysis is described. Methods of production of site-directed, segmental, and domain-specific labeling of proteins by the synthetic, semisynthetic, and recombinant strategies, including advanced protein engineering technologies such as nonsense suppression and frameshift quadruplet codons are overviewed.

WD repeat domain 43 as a new predictive indicator and its connection with tumor immune cell infiltration in pan-cancer

BACKGROUND

WD repeat domain 43 (WDR43) is a protein component that encodes WD-repeats and is involved in ribosome biogenesis. However, little is known about the role of WDR43 in cancer prognosis and immune modulation.

METHODS

In this study, we analyzed the expression and prognostic significance of WDR43 in pan-cancer using the Cancer Genome Atlas, the Genotype-Tissue Expression, and the Human Protein Atlas. We also examined the differential expression of WDR43 in liver hepatocellular carcinoma (LIHC) and adjacent tissues of 48 patients using immunohistochemistry. Additionally, we investigated the correlation between WDR43 and clinical characteristics, gene alterations, tumor mutation burden, microsatellite instability, mismatch repair, tumor microenvironment, immune infiltrating cells, and immune-related genes using bioinformatics methods. Gene set enrichment analysis was conducted, and potential biological mechanisms were identified.

RESULTS

Immunohistochemistry staining showed that WDR43 was overexpressed in LIHC among 48 patients. Upregulation of WDR43 was associated with unfavorable prognosis, including overall survival in various types of cancer such as LIHC, uterine corpus endometrial cancer, head and neck squamous cell carcinoma, and pancreatic adenocarcinoma. Differential expression of WDR43 was significantly correlated with microsatellite instability, mismatch repair, and immune cell infiltration. Gene ontology annotation analysis revealed that these genes were significantly enriched in immune-related functions, including immune response, immune regulation, and signaling pathways.

CONCLUSION

We conducted a thorough investigation of the clinical features, phases of tumor development, immune infiltration, gene mutation, and functional enrichment analysis of WDR43 in various types of cancer. This research offers valuable insight into the significance and function of WDR43 in clinical therapy.

Expression of modified FcγRI enables myeloid cells to elicit robust tumor-specific cytotoxicity

Despite the central role of T cells in tumor immunity, attempts to harness their cytotoxic capacity as a therapy have met limited efficacy, partially as a result of the suppressive microenvironment which limits their migration and activation. In contrast, myeloid cells massively infiltrate tumors and are well adapted to survive these harsh conditions. While they are equipped with cell-killing abilities, they often adopt an immunosuppressive phenotype upon migration to tumors. Therefore, the questions of how to modify their activation programming against cancer, and what signaling cascades should be activated in myeloid cells to elicit their cytotoxicity have remained unclear. Here, we found that activation of IgM-induced signaling in murine myeloid cells results in secretion of lytic granules and massive tumor cell death. These findings open venues for designing novel immunotherapy by equipping monocytes with chimeric receptors that target tumor antigens and consequently, signal through IgM receptor. Nonetheless, we found that myeloid cells do not express the antibody-derived portion used to recognize the tumor antigen due to the induction of an ER stress response. To overcome this limitation, we designed chimeric receptors that are based on the high-affinity FcγRI for IgG. Incubation of macrophages expressing these receptors along with tumor-binding IgG induced massive tumor cell killing and secretion of reactive oxygen species and Granzyme B. Overall, this work highlights the challenges involved in genetically reprogramming the signaling in myeloid cells and provides a framework for endowing myeloid cells with antigen-specific cytotoxicity.

Machine learning predictions of T cell antigen specificity from intracellular calcium dynamics

Adoptive T cell therapies rely on the production of T cells with an antigen receptor that directs their specificity toward tumor-specific antigens. Methods for identifying relevant T cell receptor (TCR) sequences, predominantly achieved through the enrichment of antigen-specific T cells, represent a major bottleneck in the production of TCR-engineered cell therapies. Fluctuation of intracellular calcium is a proximal readout of TCR signaling and candidate marker for antigen-specific T cell identification that does not require T cell expansion; however, calcium fluctuations downstream of TCR engagement are highly variable. We propose that machine learning algorithms may allow for T cell classification from complex datasets such as polyclonal T cell signaling events. Using deep learning tools, we demonstrate accurate prediction of TCR-transgenic CD8+ T cell activation based on calcium fluctuations and test the algorithm against T cells bearing a distinct TCR as well as polyclonal T cells. This provides the foundation for an antigen-specific TCR sequence identification pipeline for adoptive T cell therapies.

Expression signature of ten small nuclear RNAs serves as novel biomarker for prognosis prediction of acute myeloid leukemia

This study aimed to screen for small nuclear RNAs (snRNAs) associated with the prognosis of acute myeloid leukemia (AML) by using The Cancer Genome Atlas (TCGA) whole-transcriptome sequencing dataset. A total of 130 AML patients from TCGA cohort with complete prognostic information and transcriptome data were enrolled in the current study. Comprehensive survival and functional enrichment analyses were performed to explore the prognostic value and potential biological functions of prognostic snRNAs in AML patients. In the current study, we screened 72 snRNAs that were notably associated with the clinical outcome of AML and developed an expression signature consist of ten snRNAs, that can be accurately applied to assess the overall survival of AML patients. Functional mechanism analysis revealed that this expression signature may be strongly linked to some classical tumor-associated pathways, such as Notch and Wnt pathways, as well as being closely related to B and T cell receptor pathways. Furthermore, we screened six compounds (chicago sky blue 6 B, 5230742, clorsulon, nefopam, nicardipine, and streptomycin) that may serve as targeted therapeutic drugs for AML using connectivity maps. Tumor immunoassays indicated significant differences in the immune microenvironment of the bone marrow tissue between high-risk and low-risk AML patients. Immune infiltration analysis also revealed significant differences in the abundance of multiple immune cells in the bone marrow of the two groups of AML patients groups. In conclusion, our results revealed a novel prognostic expression signature of AML consisting of ten snRNAs, and we conducted a preliminary exploration of its potential biological functions and tumor immunity.

The landscape of T cell antigens for cancer immunotherapy

The remarkable capacity of immunotherapies to induce durable regression in some patients with metastatic cancer relies heavily on T cell recognition of tumor-presented antigens. As checkpoint-blockade therapy has limited efficacy, tumor antigens have the potential to be exploited for complementary treatments, many of which are already in clinical trials. The surge of interest in this topic has led to the expansion of the tumor antigen landscape with the emergence of new antigen categories. Nonetheless, how different antigens compare in their ability to elicit efficient and safe clinical responses remains largely unknown. Here, we review known cancer peptide antigens, their attributes and the relevant clinical data and discuss future directions.

SMAC mimetics inhibit human T cell proliferation and fail to augment type 1 cytokine responses

Second mitochondria-derived activator of caspases (SMAC) mimetics are small molecule drugs that mimic the activity of the endogenous SMAC protein. SMAC and SMAC mimetics antagonize inhibitors of apoptosis proteins (IAPs), thereby sensitizing cells to apoptosis. As such, SMAC mimetics are being tested in numerous clinical trials for cancer. In addition to their direct anti-cancer effect, it has been suggested that SMAC mimetics may activate T cells, thereby promoting anti-tumor immunity. Here, we tested the effect of three clinically relevant SMAC mimetics on activation of primary human T cells. As previously reported, SMAC mimetics killed tumor cells and activated non-canonical NF-κB in T cells at clinically relevant doses. Surprisingly, none of the SMAC mimetics augmented T cell responses. Rather, SMAC mimetics impaired T cell proliferation and decreased the proportion of IFNγ/TNFα double-producing T cells. These results question the assumption that SMAC mimetics are likely to boost anti-tumor immunity in cancer patients.

Targeting protein phosphatases in cancer immunotherapy and autoimmune disorders

Protein phosphatases act as key regulators of multiple important cellular processes and are attractive therapeutic targets for various diseases. Although extensive effort has been dedicated to phosphatase-targeted drug discovery, early expeditions for competitive phosphatase inhibitors were plagued by druggability issues, leading to the stigmatization of phosphatases as difficult targets. Despite challenges, persistent efforts have led to the identification of several drug-like, non-competitive modulators of some of these enzymes - including SH2 domain-containing protein tyrosine phosphatase 2, protein tyrosine phosphatase 1B, vascular endothelial protein tyrosine phosphatase and protein phosphatase 1 - reigniting interest in therapeutic targeting of phosphatases. Here, we discuss recent progress in phosphatase drug discovery, with emphasis on the development of selective modulators that exhibit biological activity. The roles and regulation of protein phosphatases in immune cells and their potential as powerful targets for immuno-oncology and autoimmunity indications are assessed.

Two-dimensional measurements of receptor-ligand interactions

Gaining insight into the two-dimensional receptor-ligand interactions, which play a significant role in various pivotal biological processes such as immune response and cancer metastasis, will deepen our understanding of numerous physiological and pathological mechanisms and contribute to biomedical applications and drug design. A central issue involved is how to measure the in situ receptor-ligand binding kinetics. Here, we review several representative mechanical-based and fluorescence-based methods, and briefly discuss the strengths and weaknesses for each method. In addition, we emphasize the great importance of the combination of experimental and computational methods in studying the receptor-ligand interactions, and further studies should focus on the synergistic development of experimental and computational methods.

PD-1 limits differentiation and plasticity of Tc17 cells

Blockade of surface co-inhibitory receptor programmed cell death-1 (PD-1; CD279) has been established as an important immunotherapeutic approach to treat malignancies. On a cellular level, PD-1 is demonstrated to be of particular importance in inhibiting differentiation and effector function of cytotoxic Tc1 cells (CTLs). Nevertheless, the role of PD-1 in modulating interleukin (IL)-17-producing CD8⁺ T-cells (Tc17 cells), which generally display suppressed cytotoxic nature, is not well understood. To evaluate the impact of PD-1 in Tc17 responses, we examined its functioning using different in vitro and in vivo models. Upon activation of CD8⁺ T-cells in Tc17 environment, we found that PD-1 was rapidly expressed on the surface of CD8⁺ T-cells and triggered a T-cell-internal mechanism that inhibited the expression of IL-17 and Tc17-supporting transcription factors pSTAT3 and RORγt. Expression of type17-polarising cytokine IL-21 and the receptor for IL-23 were also suppressed. Intriguingly, adoptively transferred, PD-1^-/- Tc17 cells were highly efficient in rejection of established B16 melanoma in vivo and displayed Tc1 like characteristics ex vivo. When using IL-17A-eGFP reporter mice for in vitro fate tracking, IL-17A-eGFP expressing cells lacking PD-1 signaling upon re-stimulation with IL-12 quickly acquired Tc1 characteristics such as IFN-γ, and granzyme B expression, implicating lineage independent upregulation of CTL-characteristics that are needed for tumor control. In line with plasticity characteristics, absence of PD-1 signaling in Tc17 cells increased the expression of the stemness and persistence-associated molecules TCF1 and BCL6. Thus, PD-1 plays a central role in the specific suppression of Tc17 differentiation and its plasticity in relation to CTL-driven tumor rejection, which provides further explanation as to why the blockade of PD-1 is such an efficient therapeutic target for inducing tumor rejection.

CD8 T cell function and cross-reactivity explored by stepwise increased peptide-HLA versus TCR affinity

Recruitment and activation of CD8 T cells occur through specific triggering of T cell receptor (TCR) by peptide-bound human leucocyte antigen (HLA) ligands. Within the generated trimeric TCR-peptide:HLA complex, the molecular binding affinities between peptide and HLA, and between TCR and peptide:HLA both impact T cell functional outcomes. However, how their individual and combined effects modulate immunogenicity and overall T cell responsiveness has not been investigated systematically. Here, we established two panels of human tumor peptide variants differing in their affinity to HLA. For precise characterization, we developed the “blue peptide assay”, an upgraded cell-based approach to measure the peptide:HLA affinity. These peptide variants were then used to investigate the cross-reactivity of tumor antigen-specific CD8 T cell clonotypes derived from blood of cancer patients after vaccination with either the native or an affinity-optimized Melan-A/MART-1 epitope, or isolated from tumor infiltrated lymph nodes (TILNs). Vaccines containing the native tumor epitope generated T cells with better functionality, and superior cross-reactivity against potential low affinity escape epitopes, as compared to T cells induced by vaccines containing an HLA affinity-optimized epitope. Comparatively, Melan-A/MART-1-specific TILN cells displayed functional and cross-reactive profiles that were heterogeneous and clonotype-dependent. Finally, we took advantage of a collection of T cells expressing affinity-optimized NY-ESO-1-specific TCRs to interrogate the individual and combined impact of peptide:HLA and TCR-pHLA affinities on overall CD8 T cell responses. We found profound and distinct effects of both biophysical parameters, with additive contributions and absence of hierarchical dominance. Altogether, the biological impact of peptide:HLA and TCR-pHLA affinities on T cell responses was carefully dissected in two antigenic systems, frequently targeted in human cancer immunotherapy. Our technology and stepwise comparison open new insights into the rational design and selection of vaccine-associated tumor-specific epitopes and highlight the functional and cross-reactivity profiles that endow T cells with best tumor control capacity.

The promising immune checkpoint LAG-3 in cancer immunotherapy: from basic research to clinical application

LAG-3, a type of immune checkpoint receptor protein belonging to the immunoglobulin superfamily, is confirmed to be expressed on activated immune cells, mainly including activated T cells. LAG-3 can negatively regulate the function of T cells, exerting important effects on maintaining the homeostasis of the immune system under normal physiological conditions and promoting tumor cells immune escape in the tumor microenvironment. Given its important biological roles, LAG-3 has been regarded as a promising target for cancer immunotherapy. To date, many LAG-3 inhibitors have been reported, which can be divided into monoclonal antibody, double antibody, and small molecule drug, some of which have entered the clinical research stage. LAG-3 inhibitors can negatively regulate and suppress T cell proliferation and activation through combination with MHC II ligand. Besides, LAG-3 inhibitors can also affect T cell function via binding to Galectin-3 and LSECtin. In addition, LAG-3 inhibitors can prevent the FGL1-LAG-3 interaction, thereby enhancing the human body’s antitumor immune effect. In this review, we will describe the function of LAG-3 and summarize the latest LAG-3 inhibitors in the clinic for cancer therapy.

Promoting the formation of Pi-stacking interaction to improve CTL cells activation between modified peptide and HLA

OBJECTIVE

This study aims to investigate the use of single residue substitution to promote the formation of pi-stacking interactions between peptides and Human leukocyte antigen (HLA)-A*2402 molecules to improve the affinity of peptides and HLA molecules, as well as the level of cytotoxic T lymphocyte (CTL) cells activated by peptides-HLA (p-HLA) complex.

METHODS

Molecular docking and molecular dynamics simulation were used to simulate and analyze the interactions and binding free energies between HLA-A*2402-restricted antigen peptides and HLA molecules, before and after the single residue substitution. HLA-A*2402 restricted antigen peptides before and after the single residue replacement were loaded into dendritic cells (DCs) in vitro, and further Enzyme-Linked ImmunoSpot (ELispot) test was carried out to evaluate the effect of modified antigen peptides on the immune activation of CTL cells.

RESULT

After replacing the antigen peptides with a single residue, some of them could promote the formation of pi-stacking interaction. The binding free energy between the modified antigen peptides and HLA-A*2402, as well as the level of immune activation of CTL cells were mostly higher than before, especially after the replacement of the 9th residue of the polypeptide, such as C9F and C9W. There was a significant negative correlation between the level of activated CTL cells by modified antigen peptides and the total interaction amount of hydrogen bonds and salt bridges.

CONCLUSION

Promoting the formation of pi-stacking interaction between antigen peptides and HLA-A*2402 molecules could increase the total binding free energy of p-HLA complex and the level of CTL cells activation. In addition, the amount of hydrogen bonds and salt bridges between peptides and HLA could reduce the level of immune activation. All the characteristics above can improve the immunogenicities of the weak antigens.

Tuning T cell receptor sensitivity through catch bond engineering

Adoptive cell therapy using engineered T cell receptors (TCRs) is a promising approach for targeting cancer antigens, but tumor-reactive TCRs are often weakly responsive to their target ligands, peptide-major histocompatibility complexes (pMHCs). Affinity-matured TCRs can enhance the efficacy of TCR-T cell therapy but can also cross-react with off-target antigens, resulting in organ immunopathology. We developed an alternative strategy to isolate TCR mutants that exhibited high activation signals coupled with low-affinity pMHC binding through the acquisition of catch bonds. Engineered analogs of a tumor antigen MAGE-A3-specific TCR maintained physiological affinities while exhibiting enhanced target killing potency and undetectable cross-reactivity, compared with a high-affinity clinically tested TCR that exhibited lethal cross-reactivity with a cardiac antigen. Catch bond engineering is a biophysically based strategy to tune high-sensitivity TCRs for T cell therapy with reduced potential for adverse cross-reactivity.

CD8+ T cell differentiation and dysfunction in cancer

CD8⁺ T cells specific for cancer cells are detected within tumours. However, despite their presence, tumours progress. The clinical success of immune checkpoint blockade and adoptive T cell therapy demonstrates the potential of CD8⁺ T cells to mediate antitumour responses; however, most patients with cancer fail to achieve long-term responses to immunotherapy. Here we review CD8⁺ T cell differentiation to dysfunctional states during tumorigenesis. We highlight similarities and differences between T cell dysfunction and other hyporesponsive T cell states and discuss the spatio-temporal factors contributing to T cell state heterogeneity in tumours. An important challenge is predicting which patients will respond to immunotherapeutic interventions and understanding which T cell subsets mediate the clinical response. We explore our current understanding of what determines T cell responsiveness and resistance to immunotherapy and point out the outstanding research questions.

Evaluation of the TCR Repertoire as a Predictive and Prognostic Biomarker in Cancer: Diversity or Clonality?

Simple Summary

The TCR is the T cell antigen receptor, and it is responsible of the T cell activation, through the HLA-antigen complex recognition. Studying the TCR repertoire in patients with cancer can help to better understand the anti-tumoural responses and it has been suggested to have predictive and or/prognostic values, both for the disease and in response to treatments. The aim of this review is to summarize TCR repertoire studies performed in patients with cancer found in the literature, thoroughly analyse the different factors that can be involved in shaping the TCR repertoire, and draw the current conclusions in this field, especially focusing on whether the TCR diversity—or its opposite, the clonality—can be used as predictors or prognostic biomarkers of the disease.

Abstract

T cells play a vital role in the anti-tumoural response, and the presence of tumour-infiltrating lymphocytes has shown to be directly correlated with a good prognosis in several cancer types. Nevertheless, some patients presenting tumour-infiltrating lymphocytes do not have favourable outcomes. The TCR determines the specificities of T cells, so the analysis of the TCR repertoire has been recently considered to be a potential biomarker for patients’ progression and response to therapies with immune checkpoint inhibitors. The TCR repertoire is one of the multiple elements comprising the immune system and is conditioned by several factors, including tissue type, tumour mutational burden, and patients’ immunogenetics. Its study is crucial to understanding the anti-tumoural response, how to beneficially modulate the immune response with current or new treatments, and how to better predict the prognosis. Here, we present a critical review including essential studies on TCR repertoire conducted in patients with cancer with the aim to draw the current conclusions and try to elucidate whether it is better to encounter higher clonality with few TCRs at higher frequencies, or higher diversity with many different TCRs at lower frequencies.

Strategies for Manipulating T Cells in Cancer Immunotherapy

T cells are attractive targets for the development of immunotherapy to treat cancer due to their biological features, capacity of cytotoxicity, and antigen-specific binding of receptors. Novel strategies that can modulate T cell functions or receptor reactivity provide effective therapies, including checkpoint inhibitor, bispecific antibody, and adoptive transfer of T cells transduced with tumor antigen-specific receptors. T cell-based therapies have presented successful pre-clinical/clinical outcomes despite their common immune-related adverse effects. Ongoing studies will allow us to advance current T cell therapies and develop innovative personalized T cell therapies. This review summarizes immunotherapeutic approaches with a focus on T cells. Anti-cancer T cell therapies are also discussed regarding their biological perspectives, efficacy, toxicity, challenges, and opportunities.

TCR signal strength defines distinct mechanisms of T cell dysfunction and cancer evasion

T cell receptor (TCR) signal strength is a key determinant of T cell responses. We developed a cancer mouse model in which tumor-specific CD8 T cells (TST cells) encounter tumor antigens with varying TCR signal strength. High-signal-strength interactions caused TST cells to up-regulate inhibitory receptors (IRs), lose effector function, and establish a dysfunction-associated molecular program. TST cells undergoing low-signal-strength interactions also up-regulated IRs, including PD1, but retained a cell-intrinsic functional state. Surprisingly, neither high- nor low-signal-strength interactions led to tumor control in vivo, revealing two distinct mechanisms by which PD1hi TST cells permit tumor escape; high signal strength drives dysfunction, while low signal strength results in functional inertness, where the signal strength is too low to mediate effective cancer cell killing by functional TST cells. CRISPR-Cas9-mediated fine-tuning of signal strength to an intermediate range improved anti-tumor activity in vivo. Our study defines the role of TCR signal strength in TST cell function, with important implications for T cell-based cancer immunotherapies.

T-cell receptor-based therapy: an innovative therapeutic approach for solid tumors

T-cell receptor (TCR)-based adoptive therapy employs genetically modified lymphocytes that are directed against specific tumor markers. This therapeutic modality requires a structured and integrated process that involves patient screening (e.g., for HLA-A*02:01 and specific tumor targets), leukapheresis, generation of transduced TCR product, lymphodepletion, and infusion of the TCR-based adoptive therapy. In this review, we summarize the current technology and early clinical development of TCR-based therapy in patients with solid tumors. The challenges of TCR-based therapy include those associated with TCR product manufacturing, patient selection, and preparation with lymphodepletion. Overcoming these challenges, and those posed by the immunosuppressive microenvironment, as well as developing next-generation strategies is essential to improving the efficacy and safety of TCR-based therapies. Optimization of technology to generate TCR product, treatment administration, and patient monitoring for adverse events is needed. The implementation of novel TCR strategies will require expansion of the TCR approach to patients with HLA haplotypes beyond HLA-A*02:01 and the discovery of novel tumor markers that are expressed in more patients and tumor types. Ongoing clinical trials will determine the ultimate role of TCR-based therapy in patients with solid tumors.

Testing Cancer Immunotherapy in a Human Immune System Mouse Model: Correlating Treatment Responses to Human Chimerism, Therapeutic Variables and Immune Cell Phenotypes

Over the past decade, immunotherapies have revolutionized the treatment of cancer. Although the success of immunotherapy is remarkable, it is still limited to a subset of patients. More than 1500 clinical trials are currently ongoing with a goal of improving the efficacy of immunotherapy through co-administration of other agents. Preclinical, small-animal models are strongly desired to increase the pace of scientific discovery, while reducing the cost of combination drug testing in humans. Human immune system (HIS) mice are highly immune-deficient mouse recipients rtpeconstituted with human hematopoietic stem cells. These HIS-mice are capable of growing human tumor cell lines and patient-derived tumor xenografts. This model allows rapid testing of multiple, immune-related therapeutics for tumors originating from unique clinical samples. Using a cord blood-derived HIS-BALB/c-Rag2nullIl2rγnullSIRPαNOD (BRGS) mouse model, we summarize our experiments testing immune checkpoint blockade combinations in these mice bearing a variety of human tumors, including breast, colorectal, pancreatic, lung, adrenocortical, melanoma and hematological malignancies. We present in-depth characterization of the kinetics and subsets of the HIS in lymph and non-lymph organs and relate these to protocol development and immune-related treatment responses. Furthermore, we compare the phenotype of the HIS in lymph tissues and tumors. We show that the immunotype and amount of tumor infiltrating leukocytes are widely-variable and that this phenotype is tumor-dependent in the HIS-BRGS model. We further present flow cytometric analyses of immune cell subsets, activation state, cytokine production and inhibitory receptor expression in peripheral lymph organs and tumors. We show that responding tumors bear human infiltrating T cells with a more inflammatory signature compared to non-responding tumors, similar to reports of "responding" patients in human immunotherapy clinical trials. Collectively these data support the use of HIS mice as a preclinical model to test combination immunotherapies for human cancers, if careful attention is taken to both protocol details and data analysis.

Biomechanics of T Cell Dysfunctions in Chronic Diseases

Understanding the mechanisms behind T cell dysfunctions during chronic diseases is critical in developing effective immunotherapies. As demonstrated by several animal models and human studies, T cell dysfunctions are induced during chronic diseases, spanning from infections to cancer. Although factors governing the onset and the extent of the functional impairment of T cells can differ during infections and cancer, most dysfunctional phenotypes share common phenotypic traits in their immune receptor and biophysical landscape. Through the latest developments in biophysical techniques applied to explore cell membrane and receptor-ligand dynamics, we are able to dissect and gain further insights into the driving mechanisms behind T cell dysfunctions. These insights may prove useful in developing immunotherapies aimed at reinvigorating our immune system to fight off infections and malignancies more effectively. The recent success with checkpoint inhibitors in treating cancer opens new avenues to develop more effective, targeted immunotherapies. Here, we highlight the studies focused on the transformation of the biophysical landscape during infections and cancer, and how T cell biomechanics shaped the immunopathology associated with chronic diseases.

Current advancements and future perspectives of immunotherapy in colorectal cancer research

5-Fluorouracil (5-FU) is the first-line chemotherapy drug for colorectal cancer but most of the patients get resistant to the drug on a longer course of treatment. After the successful use of immunotherapy in melanoma treatment, it was explored with enthusiasm in different types of solid cancers including colorectal cancer. Nivolumab and pembrolizumab (Programmed cell death-1 blocking antibodies) have shown efficacy in the mismatch repair deficient high microsatellite instability (dMMR-MSI-H) subtype of metastatic colorectal cancer (CRC) patients. Immunotherapy has shown long time remission in a subset of metastatic CRC patients. The molecular mechanism and emerging roles of immunotherapy in colorectal cancer are explored in this review article and future directions for the proper utilization of the development in immunobiology are suggested.