OMIP-090: A 20-parameter flow cytometry panel for rapid analysis of cell diversity and homing capacity in human conventional and regulatory T cells

Cysteine-S-sulfate promotes arteriosclerosis obliterans by inducing TH17 differentiation and promoting pyroptosis

Arteriosclerotic obliterans (ASO) is a peripheral vascular disease with a high rate of amputation, the mechanism of which remains unclear and markers for early diagnosis are seriously lacking. Therefore, we first used untargeted metabolomics analysis to reveal significant differences in metabolites between the ASO cohort and the healthy volunteer cohort. Combined with targeted analysis, it was confirmed that cysteine-S-sulfate could be identified as a potential biomarker for ASO, with good diagnostic performance. In addition, we analyzed the distribution of helper T cells (TH1, TH2, TH9, TH17 and TH22), and the results showed that TH17 was highly expressed in the ASO cohort, and IL-17 was also elevated. Through in vitro experiments, we found that cysteine-S-sulfate can promote IL-17 secretion and induce HUVCEs pyroptosis. To further clarify the pathogenicity of cysteine-S-sulfate, we used an acute lower limb ischemia model and gave a high methionine diet to simulate the high cysteine-S-sulfate state in vivo. What was shocking was that the high methionine diet group mice had lower blood flow than the control group, as well as higher levels of cysteine-S-sulfate, higher levels of TH17, and higher levels of pyroptosis. This also confirms that cysteine-S-sulfate promotes the differentiation of TH17, the secretion of cytokines, and the occurrence of pyroptosis, promoting the progression of ASO. This study is valuable in providing a diagnostic marker for ASO and elucidating its pathogenesis. This suggests that blocking IL-17 may be a new strategy to treat ASO, offering clinicians a therapeutic possibility.

OMIP-112: 42-Parameter (40-Color) Spectral Flow Cytometry Panel for Comprehensive Immunophenotyping of Human Peripheral Blood Leukocytes

Profiling the human immune system is essential to understanding its role in disease, but it requires advanced and novel technologies. Spectral flow cytometry (SFM) enables deep profiling at the single-cell level. It is able to detect many fluorescent parameters within one measurement; therefore, it is vastly useful when patient material is limited. However, designing and analyzing these high-dimensional datasets remains complex. We optimized a 42-parameter panel (40 commercially available fluorochromes, one stacked fluorochrome and an autofluorescent (AF) parameter) that enables the identification of innate and adaptive immune cell composition. It is the first 42-parameter panel that is optimized on peripheral whole blood, and it outperforms other published OMIPs of 40 colors in terms of complexity. With this panel, we are able to identify neutrophils, basophils, eosinophils, monocytes, dendritic cells, CD4 T cells, CD8 T cells, regulatory T cells, mucosal-associated invariant T (MAIT) cells, γδ T cells, B cells, NK cells, dendritic cells, and innate lymphoid cells (ILCs). Furthermore, with the utilization of co-stimulatory, checkpoint, activation, homing, and maturation markers, this panel enables deeper phenotyping. Within one measurement, more than 80 distinct immune cell subsets were identified by FlowSOM and annotated manually. In conclusion, with this high-dimensional SFM panel, we aim to generate immune profiles to understand disease and monitor therapy response.

Lymphocyte Subset Imbalance in Cardiometabolic Diseases: Are T Cells the Missing Link?

Cardiometabolic and cardiovascular diseases (CVDs) remain the leading cause of death worldwide, with well-established risk factors such as smoking, obesity, and diabetes contributing to plaque formation and chronic inflammation. However, emerging evidence suggests that the immune system plays a more significant role in the development and progression of CVD than previously thought. Specifically, the finely tuned regulation of lymphocyte subsets governs post-injury inflammation and tissue damage resolution and orchestrates the functions and activation of endothelial cells, cardiomyocytes, and fibroblasts in CVD-associated lesions (e.g., atherosclerotic plaques). A deeper understanding of the immune system's involvement in CVD development and progression will provide new insights into disease biology and uncover novel therapeutic targets aimed at re-establishing immune homeostasis. In this review, we summarize the current state of knowledge on the distribution and involvement of lymphocyte subsets in CVD, including atherosclerosis, diabetes, hypertension, myocardial infarction, and stroke.

Using Spectral Flow Cytometry for CAR T-Cell Clinical Trials: Game Changing Technologies Enabling Novel Therapies

Monitoring chimeric antigen redirected (CAR) T-cells post-infusion in clinical trials is a specialized application of flow cytometry. Unlike the CAR T-cell monitoring for individual patients conducted in clinical laboratories, the data generated during a clinical trial will be used not only to monitor the therapeutic response of a single patient, but determine the success of the therapy itself, or even of an entire class of therapeutic compounds. The data, typically acquired at multiple testing laboratories, will be compiled into a single database. The data may also be used for mathematical modeling of cellular kinetics or to identify predictive biomarkers. With the expanded context of use, a robust, standardized assay is mandatory in order to generate a valuable and reliable data set. Hence, the requirements for assay validation, traceable calibration, technology transfer, cross-instrument standardization and regulatory compliance are high.

Treg Cell Therapeutic Strategies for Breast Cancer: Holistic to Local Aspects

Regulatory T cells (Tregs) play a key role in maintaining immune homeostasis and preventing autoimmunity through their immunosuppressive function. There have been numerous reports confirming that high levels of Tregs in the tumor microenvironment (TME) are associated with a poor prognosis, highlighting their role in promoting an immunosuppressive environment. In breast cancer (BC), Tregs interact with cancer cells, ultimately leading to the suppression of immune surveillance and promoting tumor progression. This review discusses the dual role of Tregs in breast cancer, and explores the controversies and therapeutic potential associated with targeting these cells. Researchers are investigating various strategies to deplete or inhibit Tregs, such as immune checkpoint inhibitors, cytokine antagonists, and metabolic inhibition. However, the heterogeneity of Tregs and the variable precision of treatments pose significant challenges. Understanding the functional diversity of Tregs and the latest advances in targeted therapies is critical for the development of effective therapies. This review highlights the latest approaches to Tregs for BC treatment that both attenuate Treg-mediated immunosuppression in tumors and maintain immune tolerance, and advocates precise combination therapy strategies to optimize breast cancer outcomes.

Targeting T regulatory (Treg) cells in immunotherapy-resistant cancers

Primary or secondary (i.e., acquired) resistance is a common occurrence in cancer patients and is often associated with high numbers of T regulatory (Treg) cells (CD4+CD25+FOXP3+). The approval of ipilimumab and the development of similar pharmacological agents targeting cell surface proteins on Treg cells demonstrates that such intervention may overcome resistance in cancer patients. Hence, the clinical development and subsequent approval of Cytotoxic T Lymphocyte Antigen-4 (CTLA-4) targeting agents can serve as a prototype for similar agents. Such new agents aspire to be highly specific and have a reduced toxicity profile while increasing effector T cell function or effector T/T regulatory (Teff/Treg) ratio. While clinical development with large molecules has shown the greatest advancement, small molecule inhibitors that target immunomodulation are increasingly entering early clinical investigation. These new small molecule inhibitors often target specific intracellular signaling pathways [e.g., phosphoinositide-3-kinase delta (PI3K-δ)] that play an important role in regulating the function of Treg cells. This review will summarize the lessons currently applied to develop novel clinical agents that target Treg cells.

Th22 is the effector cell of thymosin β15-induced hair regeneration in mice

BACKGROUND

Thymosin beta family has a significant role in promoting hair regeneration, but which type of T cells play a key role in this process has not been deeply studied. This research aimed to find out the subtypes of T cell that play key role in hair regeneration mediated by thymosin beta 15 (Tβ15).

METHODS

Ready-to-use adenovirus expressing mouse Tmsb15b (thymosin beta 15 overexpression, Tβ15 OX) and lentivirus-Tβ15 short hairpin RNA (Tβ15 sh) were used to evaluate the role of Tβ15 in hair regeneration and development. The effect of Th22 cells on hair regeneration was further studied by optimized Th22-skewing condition medium and IL-22 binding protein (IL-22BP, an endogenous antagonist of IL-22, also known as IL-22RA2) in both ex vivo culture C57BL/6J mouse skin and BALB/c nude mice transplanted with thymus organoid model.

RESULTS

The results show that Tβ15, the homologous of Tβ4, can promote hair regeneration by increasing the proliferation activity of hair follicle cells. In addition, high-level expression of Tβ15 can not only increase the number of Th22 cells around hair follicles but also accelerate the transformation of hair follicles to maturity. Consistent with the expected results, when the IL-22BP inhibitor was used to interfere with Th22, the process of hair regeneration was blocked.

CONCLUSIONS

In conclusion, Th22 is the key effector cell of Tβ15 inducing hair regeneration. Both Tβ15 and Th22 may be the potential drug targets for hair regeneration.

Highly sensitised individuals present a distinct Treg signature compared to unsensitised individuals on haemodialysis

Introduction

Highly sensitised (HS) patients represent up to 30% of patients on the kidney transplant waiting list. When they are transplanted, they have a high risk of acute/chronic rejection and long-term allograft loss. Regulatory T cells (Tregs) (CD4+CD25hiCD127lo) are T cells involved in the suppression of immune alloresponses. A particular subset, called T follicular regulatory T cells (Tfr, CXCR5+Bcl-6+), is involved in regulating interactions between T effectors and B cells within the germinal centre and can be found in peripheral blood. Therefore, we wanted to identify specific subsets of Tregs in the peripheral blood of HS individuals.

Methods

We recruited prospectively healthy volunteers (HV) (n = 9), non-sensitised patients on haemodialysis (HD) (n = 9) and HS individuals, all of whom were on haemodialysis (n = 15).

Results

We compared the Treg phenotypes of HV, HD and HS. HS patients had more CD161+ Tregs (p = 0.02) and more CD45RA-CCR7- T effectors (Teffs) (p = 0.04, memory Teffs able to home to the germinal centre) compared to HVs. HS patients had more Bcl-6+ Tregs (p < 0.05), fewer Th1-like Tregs, more Th2-like Tregs (p < 0.001) and more CD161+ (p < 0.05) Tregs compared to HD patients. This population has been described to be highly suppressive. HD had a deficiency in a Th17-like CD161+ effector Treg cluster (cluster iii., CCR6+CCR4+CXCR3- CD39+CD15s+ICOS-CCR7-CD161+) (p < 0.05).

Discussion

This is the first study presenting a deep Treg phenotype in HS patients. We confirmed that HS patients had more of a Th17-like CD161+ effector Treg from population III (CD4+CD25hiCD127loCD45RA-) compared to non-sensitised patients on HD. The clinical relevance of this highly suppressive Tregs population remains to be determined in the context of transplantation.

OMIP-090: A 20-parameter flow cytometry panel for rapid analysis of cell diversity and homing capacity in human conventional and regulatory T cells

The panel was developed and optimized for monitoring changes in homing capacity and functional diversity of human CD4+ conventional and regulatory T cell subsets. The analysis was based on expression of only surface markers in freshly isolated peripheral blood mononuclear cells (PBMCs) to reduce at minimum any alteration due to permeabilization or freezing/thawing procedures. We included markers to assess the distribution of naïve and memory populations based on the expression of CD45RA, CCR7, CD25, CD28 and CD95 in both conventional and regulatory T cells. The identification of major functional subsets was performed using CCR4, CCR6, CCR10, CXCR3 and CXCR5. Homing capacity of these subsets to skin, airway tract, gut and inflammatory lesions could finally be assessed with the markers CLA, CCR3, CCR5 and integrin β7. The panel was tested on freshly isolated PBMCs from healthy donors and patients with allergic rhinitis or autoimmune disorders.