Expression of CD45 isoforms correlates with differential proliferative responses of peripheral CD4+ and CD8+ T cells

Causality between immunocytes and polymyositis: A Mendelian randomization analysis

Polymyositis is a prominent subgroup of idiopathic inflammatory myopathy, considered to have an autoimmune etiology. However, research exploring the condition between immunocytes and polymyositis remains limited, indicating the need for further investigation to unravel these intricate associations. We employed bidirectional Mendelian randomization (MR) analysis to ascertain causality between 731 immunocytes and polymyositis. We also compared the positive immunocytes with dermatomyositis. Our primary analytical method was inverse variance weighted, supplemented by 4 other MR techniques. Additionally, Cochran Q test was performed to assess heterogeneity, MR-Egger to appraise pleiotropy, and MR-PRESSO to identify and eliminate potential outliers. Furthermore, the leave-one-out test evaluated the impact of each instrumental variable (IV) on the causal effect. The inverse variance weighted results revealed that 10 immunocytes exert a protective effect against polymyositis (P < .05, OR < 1), while 16 immunocytes are connected with an elevated risk of the disease (P < .05, OR > 1). In reverse MR, polymyositis was found to decrease the levels of 2 immune cells (P < .05, OR < 1) and elevate the expression of 5 immune cell phenotypes (P < .05, OR > 1). A complex correlation was found between polymyositis and the immunocyte phenotypes CD8, CD33dim, HLA-DR, CD11b, and CD45. Additionally, it was discovered that 15 types of immune cells share a causal relationship between polymyositis and dermatomyositis. All analyses demonstrated no heterogeneity or horizontal pleiotropy (P > .05). Our study provides compelling evidence regarding the intricate causal relationships between immunocytes and polymyositis. Polymyositis and dermatomyositis share common immunocytes' regulatory mechanisms. CD8, CD33dim, HLA-DR, CD11b, and CD45 may represent potential immune cell markers for polymyositis. These findings hold implications for planning prognosis and therapeutic strategies for polymyositis, offering novel insights for drug development.

Glycomimetic Peptides as Therapeutic Tools

The entry of peptides into glycobiology has led to the development of a unique class of therapeutic tools. Although numerous and well-known peptides are active as endocrine regulatory factors that bind to specific receptors, and peptides have been used extensively as epitopes for vaccine production, the use of peptides that mimic sugars as ligands of lectin-type receptors has opened a unique approach to modulate activity of immune cells. Ground-breaking work that initiated the use of peptides as tools for therapy identified sugar mimetics by screening phage display libraries. The peptides that have been discovered show significant potential as high-avidity, therapeutic tools when synthesized as multivalent structures. Advantages of peptides over sugars as drugs for immune modulation will be illustrated in this review.

MicroRNAs in Tumor Exosomes Drive Immune Escape in Melanoma

MicroRNAs (miRNA), small noncoding RNAs that regulate gene expression, exist not only in cells but also in a variety of body fluids. These circulating miRNAs could enable intercellular communication. miRNAs are packaged in membrane-encapsulated vesicles, such as exosomes, or protected by RNA-binding proteins. Here, we report that miRNAs included in human melanoma exosomes regulate the tumor immune response. Using microscopy and flow cytometry, we demonstrate that CD8⁺ T cells internalize exosomes from different tumor types even if these cells do not internalize vesicles as readily as other immune cells. We explored the function of melanoma-derived exosomes in CD8⁺ T cells and showed that these exosomes downregulate T-cell responses through decreased T-cell receptor (TCR) signaling and diminished cytokine and granzyme B secretions. The result reduces the cells' cytotoxic activity. Using mimics, we found that miRNAs enriched in exosomes-such as Homo sapiens (hsa)-miR-3187-3p, hsa-miR-498, hsa-miR-122, hsa-miR149, and hsa-miR-181a/b-regulate TCR signaling and TNFα secretion. Our observations suggest that miRNAs in melanoma-derived exosomes aid tumor immune evasion and could be a therapeutic target.

An innovative immunotherapeutic strategy for ovarian cancer: CLEC10A and glycomimetic peptides

BACKGROUND

Receptors specific for the sugar N-acetylgalactosamine (GalNAc) include the human type II, C-type lectin receptor macrophage galactose-type lectin/C-type lectin receptor family member 10A (MGL/CLEC10A/CD301) that is expressed prominently by human peripheral immature dendritic cells, dendritic cells in the skin, alternatively-activated (M2a) macrophages, and to lesser extents by several other types of tissues. CLEC10A is an endocytic receptor on antigen-presenting cells and has been proposed to play an important role in maturation of dendritic cells and initiation of an immune response. In this study, we asked whether a peptide that binds in the GalNAc-binding site of CLEC10A would serve as an effective tool to activate an immune response against ovarian cancer.

METHODS

A 12-mer sequence emerged from a screen of a phage display library with a GalNAc-specific lectin. The peptide, designated svL4, and a shorter peptide consisting of the C-terminal 6 amino acids, designated sv6D, were synthesized as tetravalent structures based on a tri-lysine core. In silico and in vitro binding assays were developed to evaluate binding of the peptides to GalNAc-specific receptors. Endotoxin-negative peptide solutions were administered by subcutaneous injection and biological activity of the peptides was determined by secretion of cytokines and the response of peritoneal immune cells in mice. Anti-cancer activity was studied in a murine model of ovarian cancer.

RESULTS

The peptides bound to recombinant human CLEC10A with high avidity, with half-maximal binding in the low nanomolar range. Binding to the receptor was Ca²⁺-dependent. Subcutaneous injection of low doses of peptides into mice on alternate days resulted in several-fold expansion of populations of mature immune cells within the peritoneal cavity. Peptide sv6D effectively suppressed development of ascites in a murine ovarian cancer model as a monotherapy and in combination with the chemotherapeutic drug paclitaxel or the immunotherapeutic antibody against the receptor PD-1. Toxicity, including antigenicity and release of cytotoxic levels of cytokines, was not observed.

CONCLUSION

sv6D is a functional ligand for CLEC10A and induces maturation of immune cells in the peritoneal cavity. The peptide caused a highly significant extension of survival of mice with implanted ovarian cancer cells with a favorable toxicity and non-antigenic profile.

Inflammasome activation is critical to the protective immune response during chemically induced squamous cell carcinoma

Chronic inflammation affects most stages of tumorigenesis, including initiation, promotion, malignant differentiation, invasion and metastasis. Inflammasomes have been described as involved with persistent inflammation and are known to exert both pro and antitumour effects. We evaluated the influence of apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) and caspase (CASP)-1 in the antitumor immune response using a multistage model of squamous cell carcinoma (SCC) development. Absence of ASC and CASP-1 resulted in an earlier incidence and increased number of papilloma. Loss of inflammassome function in mice resulted in decreased presence of natural killer (NK), dendritic (DC), CD4⁺, CD8⁺ and CD45RB⁺ T cells in the tumor lesions as well as in lymph nodes (LN) compared with WT mice. Increased percentage of CD4⁺CD25⁺Foxp3⁺ T cells was associated with association with inflammasome loss of function. Moreover, significant differences were also found with neutrophils and macrophage infiltrating the lesions. Myeloperoxidase (MPO), but not elastase (ELA), activity oscillated among the groups during the SCC development. Levels of proinflammatory cytokines IL-1β, IL-18, Tumor Necrosis Factor (TNF)-α and Interferon (IFN)-γ were decreased in the tumor microenvironment in the absence of inflammasome proteins. These observations suggest a link between inflammasome function and SCC tumorigenesis, indicating an important role for inflammasome activation in the control of SCC development.

Effect of administration of BMDC vaccine sensitized by heat shocked hepal-6 cell proteins on intratumoral CD25+Foxp3+ Tregs in mouse hepatocellular carcinoma

AIM: To determine whether the bone marrow derived dendritic cell (BMDC) vaccine sensitized by heat shocked hepal-6 cell proteins affects the infiltration of intratumoral CD25⁺Foxp3⁺ Tregs in a mouse hepatocellular carcinoma (HCC) model.

METHODS: In the presence of GM-CSF and IL-4, BMDCs were induced in vitro. BMDCs were sensitized by heat shocked hepal-6 cell proteins to generate a vaccine for HCC. The expression of CD11c, CCR7, CD80 and CD86 on these sensitized BMDCs were analyzed by FACS. The anti-tumor effect of this vaccine was evaluated using a mouse HCC model established by subcutaneous injection of Hepal-6 cells. Eight days later, the tumor-bearing mice were divided into four groups, which underwent intratumoral injection of BMDCs sensitized by heat shocked hepal-6 cell proteins, serum-free culture medium, BMDCs without sensitization and BMDCs sensitized by unheated hepal-6 cell proteins (once every 7 d, 2 times altogether), respectively. Nine days after final administration, the mice were sacrificed and the tumor samples were taken for immunofluorescence staining for CD8⁺ cells and intratumoral CD25⁺Foxp3⁺ Tregs.

RESULTS: Light microscopy and scanning electron microscopy showed that BMDCs propagated in the presence of GM-CSF and IL-4 displayed the typical morphological characteristics of dendritic cells. Immunocytochemical staining showed that they expressed the dendritic cell marks including CD11c, CCR7, CD80 and CD86. Compared with the controls (BMDCs without sensitization or sensitized by unheated hepal-6 cells proteins), the BMDCs sensitized by heat shocked hepal-6 cells proteins showed increased expression of CD11c (67.2 ± 4.49 vs 52.4 ± 5.20, 58.4 ± 4.43), CCR7 (65.4 ± 5.34 vs 45.9 ± 5.04, 57.0 ± 3.46), CD80 (62.9 ± 4.69 vs 46.9 ± 4.75, 54.4 ± 3.47) and CD86 (73.3 ± 3.58 vs 60.1 ± 2.98, 63.7 ± 3.10) (P < 0.01 for all). Compared with the controls, the mice administrated with the BMDC vaccine sensitized by heat shocked Hepal-6 cell proteins showed increased CD8⁺ T cells (55.0 ± 4.11 vs 38.2 ± 3.34, 44.6 ± 4.29, 45.6 ± 4.92, P < 0.01 for all) and decreased intratumoral CD25⁺Foxp3⁺ Tregs (0.37 ± 0.028 vs 1.31 ± 0.020, 0.77 ± 0.057, 0.57 ± 0.062, P < 0.05 for all).

CONCLUSION: Heat shocked hepal-6 cell protein sensitization can upregulate the expression of CD11c, CCR7, CD80 and CD86 on BMDCs in vitro. Administration with this BMDC vaccine can increase CD8⁺ T cells and decrease intratumoral CD25⁺Foxp3⁺ Tregs in HCC mice.

Regulation of TCR signalling by tyrosine phosphatases: from immune homeostasis to autoimmunity

More than half of the known protein tyrosine phosphatases (PTPs) in the human genome are expressed in T cells, and significant progress has been made in elucidating the biology of these enzymes in T-cell development and function. Here we provide a systematic review of the current understanding of the roles of PTPs in T-cell activation, providing insight into their mechanisms of action and regulation in T-cell receptor signalling, the phenotypes of their genetically modified mice, and their possible involvement in T-cell-mediated autoimmune disease. Our projection is that the interest in PTPs as mediators of T-cell homeostasis will continue to rise with further functional analysis of these proteins, and PTPs will be increasingly considered as targets of immunomodulatory therapies.

Substantially modified ratios of effector to regulatory T cells during chemotherapy in ovarian cancer patients return to pre-treatment levels at completion: implications for immunotherapy

Ovarian cancer is the leading cause of death from gynaecological malignancy. Despite improved detection and treatment options, relapse rates remain high. Combining immunotherapy with the current standard treatments may provide an improved prognosis, however, little is known about how standard chemotherapy affects immune potential (particularly T cells) over time, and hence, when to optimally combine it with immunotherapy (e.g., vaccines). Herein, we assess the frequency and ratio of CD8+ central memory and effector T cells as well as CD4+ effector and regulatory T cells (Tregs) during the first 18 weeks of standard chemotherapy for ovarian cancer patients. In this pilot study, we observed increased levels of recently activated Tregs with tumor migrating ability (CD4+CD25^hiFoxp3+CD127−CCR4+CD38+ cells) in patients when compared to controls. Although frequency changes of Tregs as well as the ratio of effector T cells to Tregs were observed during treatment, the Tregs consistently returned to pre-chemotherapy levels at the end of treatment. These results indicate T cell subset distributions associated with recurrence may be largely resistant to being “re-set” to healthy control homeostatic levels following standard treatments. However, it may be possible to enhance T effector to Treg ratios transiently during chemotherapy. These results suggest personalized immune monitoring maybe beneficial when combining novel immuno-therapeutics with standard treatment for ovarian cancer patients.