Conditions for the generation of cytotoxic CD4(+) Th cells that enhance CD8(+) CTL-mediated tumor regression

Association of clinical outcomes and the predictive value of T lymphocyte subsets within colorectal cancer patients

Introduction

Tumor immunity is a hot topic in tumor research today, and human immunity is closely related to tumor progression. T lymphocyte is an important component of human immune system, and the changes in their subsets may influence the progression of colorectal cancer (CRC) to some extent. This clinical study systematically describes and analyzes the association of CD4⁺ and CD8⁺ T-lymphocyte content and CD4⁺/CD8⁺ T-lymphocyte ratio with CRC differentiation, clinical pathological stage, Ki67 expression, T-stage, N-stage, carcinoembryonic antigen (CEA) content, nerve and vascular infiltration, and other clinical features, as well as preoperative and postoperative trends. Furthermore, a predictive model is constructed to evaluate the predictive value of T-lymphocyte subsets for CRC clinical features.

Methods

Strict inclusion and exclusion criterion were formulated to screen patients, preoperative and postoperative flow cytometry and postoperative pathology reports from standard laparoscopic surgery were assessed. PASS and SPSS software, R packages were invoked to calculate and analyze.

Results

We found that a high CD4⁺ T-lymphocyte content in peripheral blood and a high CD4⁺/CD8⁺ ratio were associated with better tumor differentiation, an earlier clinical pathological stage, lower Ki67 expression, shallower tumor infiltration, a smaller number of lymph node metastases, a lower CEA content, and a lower likelihood of nerve or vascular infiltration (P < 0.05). However, a high CD8⁺ T-lymphocyte content indicated an unpromising clinical profile. After effective surgical treatment, the CD4⁺ T-lymphocyte content and CD4⁺/CD8⁺ ratio increased significantly (P < 0.05), while the CD8⁺ T-lymphocyte content decreased significantly (P < 0.05). Further, we comprehensively compared the merits of CD4⁺ T-lymphocyte content, CD8⁺ T-lymphocyte content, and CD4⁺/CD8⁺ ratio in predicting the clinical features of CRC. We then combined the CD4⁺ and CD8⁺ T-lymphocyte content to build models and predict major clinical characteristics. We compared these models with the CD4⁺/CD8⁺ ratio to explore their advantages and disadvantages in predicting the clinical features of CRC.

Discussion

Our results provide a theoretical basis for the future screening of effective markers in reflecting and predicting the progression of CRC. Changes in T lymphocyte subsets affect the progression of CRC to a certain extent, while their changes also reflect variations in the human immune system.

Modulation of TCR Signaling by Tyrosine Phosphatases: From Autoimmunity to Immunotherapy

Early TCR signaling is dependent on rapid phosphorylation and dephosphorylation of multiple signaling and adaptor proteins, leading to T cell activation. This process is tightly regulated by an intricate web of interactions between kinases and phosphatases. A number of tyrosine phosphatases have been shown to modulate T cell responses and thus alter T cell fate by negatively regulating early TCR signaling. Mutations in some of these enzymes are associated with enhanced predisposition to autoimmunity in humans, and mouse models deficient in orthologous genes often show T cell hyper-activation. Therefore, phosphatases are emerging as potential targets in situations where it is desirable to enhance T cell responses, such as immune responses to tumors. In this review, we summarize the current knowledge about tyrosine phosphatases that regulate early TCR signaling and discuss their involvement in autoimmunity and their potential as targets for tumor immunotherapy.

Assay and Isolation of Single Proliferating CD4+ Lymphocytes Using an Automated Microraft Array Platform

OBJECTIVE

While T lymphocytes have been employed as a cancer immunotherapy, the development of effective and specific T-cell-based therapeutics remains challenging. A key obstacle is the difficulty in identifying T cells reactive to cancer-associated antigens. The objective of this research was to develop a versatile platform for single cell analysis and isolation that can be applied in immunology research and clinical therapy development.

METHODS

An automated microscopy and cell sorting system was developed to track the proliferative behavior of single-cell human primary CD4+ lymphocytes in response to stimulation using allogeneic lymphoblastoid feeder cells.

RESULTS

The system identified single human T lymphocytes with a sensitivity of 98% and specificity of 99% and possessed a cell collection efficiency of 86%. Time-lapse imaging simultaneously tracked 4,534 alloreactive T cells on a single array; 19% of the arrayed cells formed colonies of ≥2 cells. From the array, 130 clonal colonies were isolated and 7 grew to colony sizes of >10,000 cells, consistent with the known proliferative capacity of T cells in vitro and their tendency to become exhausted with prolonged stimulation. The isolated colonies underwent ELISA assay to detect interferon-γ secretion and Sanger sequencing to determine T cell receptor β sequences with a 100% success rate.

CONCLUSION

The platform is capable of both identification and isolation of proliferative T cells in an automated manner.

SIGNIFICANCE

This novel technology enables the identification of TCR sequences based on T cell proliferation which is expected to speed the development of future cancer immunotherapies.

Tumor-intrinsic PIK3CA represses tumor immunogenecity in a model of pancreatic cancer

The presence of tumor-infiltrating T cells is associated with favorable patient outcomes, yet most pancreatic cancers are immunologically silent and resistant to currently available immunotherapies. Here we show using a syngeneic orthotopic implantation model of pancreatic cancer that Pik3ca regulates tumor immunogenicity. Genetic silencing of Pik3ca in KrasG12D/Trp53R172H-driven pancreatic tumors resulted in infiltration of T cells, complete tumor regression, and 100% survival of immunocompetent host mice. By contrast, Pik3ca-null tumors implanted in T cell-deficient mice progressed and killed all of the animals. Adoptive transfer of tumor antigen-experienced T cells eliminated Pik3ca-null tumors in immunodeficient mice. Loss of PIK3CA or inhibition of its effector, AKT, increased the expression of MHC Class I and CD80 on tumor cells. These changes contributed to the increased susceptibility of Pik3ca-null tumors to T cell surveillance. Our results indicate that tumor cell PIK3CA-AKT signaling limits T cell recognition and clearance of pancreatic cancer cells. Strategies that target this pathway may yield an effective immunotherapy for this cancer.

IFNγ PET Imaging as a Predictive Tool for Monitoring Response to Tumor Immunotherapy

IFNγ is an attractive target for imaging active antitumor immunity due to its function in the T-cell signaling axis. Here, we test an IFNγ immuno-PET (immunoPET) probe for its capacity to identify adaptive immunotherapy response after HER2/neu vaccination in both spontaneous salivary and orthotopic neu+ mouse mammary tumors. IFNγ immunoPET detected elevated cytokine levels in situ after vaccination, which inversely correlated with tumor growth rate, an indicator of response to therapy. In a model of induced T-cell anergy where CD8 T cells infiltrate the tumor, but upregulate PD-1, IFNγ tracer uptake was equivalent to isotype control, illustrating a lack of antitumor T-cell activity. The IFNγ immunoPET tracer detected IFNγ protein sequestered on the surface of tumor cells, likely in complex with the IFNγ receptor, which may explain imaging localization of this soluble factor in vivo Collectively, we find that the activation status of cytotoxic T cells is annotated by IFNγ immunoPET, with reduced off-target binding to secondary lymphoid tissues compared with imaging total CD3+ tumor-infiltrating lymphocytes. Targeting of soluble cytokines such as IFNγ by PET imaging may provide valuable noninvasive insight into the function of immune cells in situ Significance: This study presents a novel approach to monitor therapeutic outcomes via IFNγ-targeted positron emission tomography. Cancer Res; 78(19); 5706-17. ©2018 AACR.

Relationship between infiltrating lymphocytes in cancerous ascites and dysfunction of Cajal mesenchymal cells in the small intestine

Malignant ascites changes the microenvironment of the peritoneal cavity and damages abdominal functional host cells such as interstitial cells of Cajal (ICC), causing gastrointestinal dysfunction and poor prognosis. Besides tumor cells, malignant ascites contains large numbers of lymphocytes and macrophagocytes. These inflammatory cells act as a 'double arrow' and it is not clear whether they cause injury to ICCs. Our study demonstrates the presence of T lymphocytes in malignant ascites and shows that these cells may have a critical role in inducing damage to ICC via Caspases and Fas/FasL. These inflammatory cells were contributory to gastric dysfunction in our GI tumor-induced ascites mouse models.

Adoptive cell therapy with CD4+ T helper 1 cells and CD8+ cytotoxic T cells enhances complete rejection of an established tumour, leading to generation of endogenous memory responses to non-targeted tumour epitopes

The results of adoptive T-cell therapies (ACTs) are very encouraging and show clinical evidence that ACT can provide a cure for patients with metastatic disease. However, various response rates and long-term cancer remission have been observed in different ACT trials. The types of T cells, prior treatment with chemotherapy and co-administration of other immune-target therapies have been found to influence the efficacy of ACT. In this study, we investigate the ability of ACT using CD4⁺ T helper 1 (Th1) cells and CD8⁺ cytotoxic T lymphocytes (CTLs) to reject the growth of established B16-ovalbumin (OVA) melanoma. CD8⁺ CTLs were found to be the main effector T cells that mediated tumour regression. However, low tumour-free survival rates were observed in ACT with CD8⁺ CTLs only. Co-transferring CD4⁺ Th1 cells and CD8⁺ CTLs has been observed to induce a synergistic antitumour response, resulting in complete regression in 80% of the tumour-bearing mice. We also examined a prior Dacarbazine (DTIC) and after virus-like particle (VLP)-OVA vaccine treatment to enhance ACT, but no therapeutic benefit was observed during primary B16-OVA tumour growth. Nevertheless, the ACT-mediated antitumour response was able to generate memory responses to both B16-OVA and B16-gp33 tumours. VLP-OVA vaccination following ACT enhances the memory responses to tumours that express a heterogenic population of both B16-OVA and B16-gp33 cells; however, it abolished the memory response to tumours consisting of only gp33-expressing cells. These findings provide important information for designing therapeutic treatments for patients with metastatic disease and cancer relapse to achieve durable cancer remission.