γδ T cells are a kind of innate immune T cell. They have not attracted sufficient attention because they account for only a small proportion of all immune cells, and many basic factors related to these cells remain unclear. However, in recent years, with the rapid development of tumor immunotherapy, γδ T cells have attracted increasing attention because of their ability to exert cytotoxic effects on most tumor cells without major histocompatibility complex (MHC) restriction. An increasing number of basic studies have focused on the development, antigen recognition, activation, and antitumor immune response of γδ T cells. Additionally, γδ T cell-based immunotherapeutic strategies are being developed, and the number of clinical trials investigating such strategies is increasing. This review mainly summarizes the progress of basic research and the clinical application of γδ T cells in tumor immunotherapy to provide a theoretical basis for further the development of γδ T cell-based strategies in the future.
Humans ; Receptors, Antigen, T-Cell, gamma-delta ; Immunotherapy, Adoptive ; T-Lymphocytes ; Immunotherapy ; Neoplasms/therapy*

Objective To explore the phenotypic conversion of regulatory T cells (Tregs) in the lungs of mice with bronchopulmonary dysplasia (BPD)-affected mice. Methods A total of 20 newborn C57BL/6 mice were divided into air group and hyperoxia group, with 10 mice in each group. The BPD model was established by exposing the newborn mice to hyperoxia. Lung tissues from five mice in each group were collected on postnatal days 7 and 14, respectively. Histopathological changes of the lung tissues was detected by HE staining. The expression level of surfactant protein C (SP-C) in the lung tissues was examined by Western blot analysis. Flow cytometry was performed to assess the proportion of FOXP3⁺ Tregs and RORγt⁺FOXP3⁺ Tregs in CD4⁺ lymphocytes. The concentrations of interleukin-17A (IL-17A) and IL-6 in lung homogenate were measured by using ELISA. Spearman correlation analysis was used to analyze the correlation between FOXP3⁺Treg and the expression of SP-C and the correlation between RORγt⁺FOXP3⁺ Tregs and the content of IL-17A and IL-6. Results The hyperoxia group exhibited significantly decreased levels of SP-C and radical alveolar counts in comparison to the control group. The proportion of FOXP3⁺Tregs was reduced and that of RORγt⁺FOXP3⁺Tregs was increased. IL-17A and IL-6 concentrations were significantly increased. SP-C was positively correlated with the expression level of RORγt⁺FOXP3⁺ Tregs. RORγt⁺FOXP3⁺ Tregs and IL-17A and IL-6 concentrations were also positively correlated. Conclusion The number of FOXP3⁺ Tregs in lung tissue of BPD mice is decreased and converted to RORγt⁺ FOXP3⁺ Tregs, which may be involved in hyperoxy-induced lung injury.
Animals ; Mice ; Mice, Inbred C57BL ; Bronchopulmonary Dysplasia ; T-Lymphocytes, Regulatory ; Interleukin-17 ; Nuclear Receptor Subfamily 1, Group F, Member 3 ; Hyperoxia ; Interleukin-6 ; Forkhead Transcription Factors ; Lung

In the tumor microenvironment, metabolic reprogramming can impact metabolic characteristics of T cells, thus inducing immunosuppression to promote tumor immune escape. The mammalian target of rapamycin (mTOR) signaling pathway plays an important role in regulating diverse functions of various immune cells. This review mainly focuses on the molecular mechanism of mTOR signaling in regulating cellular energy metabolism process, and the activation status of mTOR signaling under different nutritional environments. In addition, it also summarizes the role of the mTOR signaling in regulatory T cell (Tregs) metabolism and function in current studies, and evaluates the potential of mTOR as a clinical immunotherapeutic target and its current application challenges.
Immunosuppression Therapy ; Metabolic Reprogramming ; Signal Transduction ; Sirolimus ; T-Lymphocytes, Regulatory ; TOR Serine-Threonine Kinases ; Humans

Multiple sclerosis (MS) is a neuroinflammatory demyelinating disease, mediated by pathogenic T helper 17 (Th17) cells. However, the therapeutic effect is accompanied by the fluctuation of the proportion and function of Th17 cells, which prompted us to find the key regulator of Th17 differentiation in MS. Here, we demonstrated that the triggering receptor expressed on myeloid cells 2 (TREM-2), a modulator of pattern recognition receptors on innate immune cells, was highly expressed on pathogenic CD4-positive T lymphocyte (CD4⁺ T) cells in both patients with MS and experimental autoimmune encephalomyelitis (EAE) mouse models. Conditional knockout of Trem-2 in CD4⁺ T cells significantly alleviated the disease activity and reduced Th17 cell infiltration, activation, differentiation, and inflammatory cytokine production and secretion in EAE mice. Furthermore, with Trem-2 knockout in vivo experiments and in vitro inhibitor assays, the TREM-2/zeta-chain associated protein kinase 70 (ZAP70)/signal transducer and activator of transcription 3 (STAT3) signal axis was essential for Th17 activation and differentiation in EAE progression. In conclusion, TREM-2 is a key regulator of pathogenic Th17 in EAE mice, and this sheds new light on the potential of this therapeutic target for MS.
Animals ; Humans ; Mice ; CD4-Positive T-Lymphocytes/pathology* ; Cell Differentiation ; Encephalomyelitis, Autoimmune, Experimental/metabolism* ; Mice, Inbred C57BL ; Multiple Sclerosis ; Th1 Cells/pathology*

OBJECTIVE: To compare the clinical efficacy between the combined therapy of fire needling and cupping, and western medication on herpes zoster of acute stage, as well as the effects on Th17 and Treg cells and inflammatory factors, i.e. IL-10 and IL-17 in the peripheral blood. METHODS: Eighty patients with herpes zoster of acute stage were randomly divided into a combined therapy (fire needling plus cupping) group and a western medication group, 40 cases in each one. In the combined therapy group, the pricking and scattering techniques with fire needle were used at ashi points and Jiaji (EX-B 2) corresponding to the affected spinal segments; afterwards, cupping therapy was delivered. The combined treatment was given once daily. In the western medication group, valaciclovir hydrochloride tablet and vitamin B₁ tablet were administered orally. The duration of treatment in each group was 10 days. Before each treatment from day 1 to day 10 and on day 11 , the score of symptoms and physical signs was observed in the two groups separately. Before each treatment from day 1 to day 10 and on day 11, 30, 60, the score of visual analogue scale (VAS) and skin lesion indexes were observed in the two groups. On day 60, the incidence of postherpetic neuralgia was recorded in the two groups. The levels of Th17 and Treg cells, Th17/Treg ratio in the peripheral blood, as well as serum levels of IL-10 and IL-17 were detected before and after treatment in the two groups. The clinical efficacy was compared between the two groups. RESULTS: From day 6 to day 10 during treatment and on day 11, the scores of symptoms and physical signs in the combined therapy group were lower than those of the western medication group (P<0.05, P<0.01). On day 3, day 6 to day 10 during treatment and day 11, day 30, VAS scores in the combined therapy group were lower than those of the western medication group (P<0.05, P<0.01). On day 60, the incidence of postherpetic neuralgia in the combined therapy group was lower compared with that in the western medication group (P<0.05). The blister arresting time and scabbing time in the combined therapy group were shorter than those of the western medication group (P<0.05). After treatment, the level of Th17, and Th17/Treg ratio in the peripheral blood, as well as the serum levels of IL-10 and IL-17 were all lower in comparison with those in the western medication group (P<0.05). The curative and remarkably effective rate was 82.5% (33/40) in the combined therapy group, higher than 62.5% (25/40) in the western medication group (P<0.05). CONCLUSION The early application of fire needling combined with cupping therapy can effectively treat herpes zoster of acute stage, relieve pain, and reduce the incidence of postherpetic neuralgia, which may be related to reducing the levels of Th17 and Treg cells, and Th17/Treg ratio in the peripheral blood, as well as the serum levels of IL-10 and IL-17 so that the cellular immune balance is modulated.
Humans ; Neuralgia, Postherpetic ; Acupuncture Therapy/methods* ; Interleukin-10 ; Interleukin-17 ; T-Lymphocytes, Regulatory ; Cupping Therapy ; Th17 Cells ; Herpes Zoster/therapy* ; Treatment Outcome ; Tablets

Humans ; Cytomegalovirus ; Cytomegalovirus Infections ; Antigens, Viral ; Immunity ; Autoimmune Diseases ; CD8-Positive T-Lymphocytes

Incomplete immune reconstitution remains a global challenge for human immunodeficiency virus (HIV) treatment in the present era of potent antiretroviral therapy (ART), especially for those individuals referred to as immunological non-responders (INRs), who exhibit dramatically low CD4 + T-cell counts despite the use of effective antiretroviral therapy, with long-term inhibition of viral replication. In this review, we provide a critical overview of the concept of ART-treated HIV-positive immunological non-response, and also explain the known mechanisms which could potentially account for the emergence of immunological non-response in some HIV-infected individuals treated with appropriate and effective ART. We found that immune cell exhaustion, combined with chronic inflammation and the HIV-associated dysbiosis syndrome, may represent strategic aspects of the immune response that may be fundamental to incomplete immune recovery. Interestingly, we noted from the literature that metformin exhibits properties and characteristics that may potentially be useful to specifically target immune cell exhaustion, chronic inflammation, and HIV-associated gut dysbiosis syndrome, mechanisms which are now recognized for their critically important complicity in HIV disease-related incomplete immune recovery. In light of evidence discussed in this review, it can be seen that metformin may be of particularly favorable use if utilized as adjunctive treatment in INRs to potentially enhance immune reconstitution. The approach described herein may represent a promising area of therapeutic intervention, aiding in significantly reducing the risk of HIV disease progression and mortality in a particularly vulnerable subgroup of HIV-positive individuals.
Humans ; Immune Reconstitution ; CD4 Lymphocyte Count ; Metformin/therapeutic use* ; Dysbiosis ; Antiretroviral Therapy, Highly Active ; HIV Infections/drug therapy* ; CD4-Positive T-Lymphocytes ; HIV ; Syndrome

Inflammation is a major underlying mechanism in the progression of numerous cardiovascular diseases (CVDs). Regulatory T cells (Tregs) are typical immune regulatory cells with recognized immunosuppressive properties. Despite the immunosuppressive properties, researchers have acknowledged the significance of Tregs in maintaining tissue homeostasis and facilitating repair/regeneration. Previous studies unveiled the heterogeneity of Tregs in the heart and aorta, which expanded in CVDs with unique transcriptional phenotypes and reparative/regenerative function. This review briefly summarizes the functional principles of Tregs, also including the synergistic effect of Tregs and other immune cells in CVDs. We discriminate the roles and therapeutic potential of Tregs in CVDs such as atherosclerosis, hypertension, abdominal arterial aneurysm, pulmonary arterial hypertension, Kawasaki disease, myocarditis, myocardial infarction, and heart failure. Tregs not only exert anti-inflammatory effects but also actively promote myocardial regeneration and vascular repair, maintaining the stability of the local microenvironment. Given that the specific mechanism of Tregs functioning in CVDs remains unclear, we reviewed previous clinical and basic studies and the latest findings on the function and mechanism of Tregs in CVDs.
Humans ; T-Lymphocytes, Regulatory ; Cardiovascular Diseases ; Atherosclerosis ; Myocardial Infarction ; Phenotype

BACKGROUND: Previous studies have examined the bulk transcriptome of peripheral blood immune cells in acquired immunodeficiency syndrome patients experiencing immunological non-responsiveness. This study aimed to investigate the characteristics of specific immune cell subtypes in acquired immunodeficiency syndrome patients who exhibit immunological non-responsiveness. METHODS: A single-cell transcriptome sequencing of peripheral blood mononuclear cells obtained from both immunological responders (IRs) (CD4 + T-cell count >500) and immunological non-responders (INRs) (CD4 + T-cell count <300) was conducted. The transcriptomic profiles were used to identify distinct cell subpopulations, marker genes, and differentially expressed genes aiming to uncover potential genetic factors associated with immunological non-responsiveness. RESULTS: Among the cellular subpopulations analyzed, the ratios of monocytes, CD16 + monocytes, and exhausted B cells demonstrated the most substantial differences between INRs and IRs, with fold changes of 39.79, 11.08, and 2.71, respectively. In contrast, the CD4 + T cell ratio was significantly decreased (0.39-fold change) in INRs compared with that in IRs. Similarly, the ratios of natural killer cells and terminal effector CD8 + T cells were also lower (0.37-fold and 0.27-fold, respectively) in the INRs group. In addition to several well-characterized immune cell-specific markers, we identified a set of 181 marker genes that were enriched in biological pathways associated with human immunodeficiency virus (HIV) replication. Notably, ISG15 , IFITM3 , PLSCR1 , HLA-DQB1 , CCL3L1 , and DDX5 , which have been demonstrated to influence HIV replication through their interaction with viral proteins, emerged as significant monocyte marker genes. Furthermore, the differentially expressed genes in natural killer cells were also enriched in biological pathways associated with HIV replication. CONCLUSIONS We generated an atlas of immune cell transcriptomes in HIV-infected IRs and INRs. Host genes associated with HIV replication were identified as markers of, and were found to be differentially expressed in, different types of immune cells.
Humans ; Acquired Immunodeficiency Syndrome ; Transcriptome/genetics* ; HIV ; HIV Infections/genetics* ; Leukocytes, Mononuclear/metabolism* ; CD4-Positive T-Lymphocytes/metabolism* ; Virus Replication ; Membrane Proteins/metabolism* ; RNA-Binding Proteins/metabolism*

BACKGROUND: T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT), an inhibitory receptor expressed on T cells, plays a dysfunctional role in antiviral infection and antitumor activity. However, it is unknown whether TIGIT expression on T cells influences the immunological effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccines. METHODS: Forty-five people living with HIV (PLWH) on antiretroviral therapy (ART) for more than two years and 31 healthy controls (HCs), all received a third dose of a SARS-CoV-2 inactivated vaccine, were enrolled in this study. The amounts, activation, proportion of cell subsets, and magnitude of the SARS-CoV-2-specific immune response of TIGIT + CD4 + and TIGIT + CD8 + T cells were investigated before the third dose but 6 months after the second vaccine dose (0W), 4 weeks (4W) and 12 weeks (12W) after the third dose. RESULTS: Compared to that in HCs, the frequency of TIGIT + CD8 + T cells in the peripheral blood of PLWH increased at 12W after the third dose of the inactivated vaccine, and the immune activation of TIGIT + CD8 + T cells also increased. A decrease in the ratio of both T naïve (T N ) and central memory (T CM ) cells among TIGIT + CD8 + T cells and an increase in the ratio of the effector memory (T EM ) subpopulation were observed at 12W in PLWH. Interestingly, particularly at 12W, a higher proportion of TIGIT + CD8 + T cells expressing CD137 and CD69 simultaneously was observed in HCs than in PLWH based on the activation-induced marker assay. Compared with 0W, SARS-CoV-2-specific TIGIT + CD8 + T-cell responses in PLWH were not enhanced at 12W but were enhanced in HCs. Additionally, at all time points, the SARS-CoV-2-specific responses of TIGIT + CD8 + T cells in PLWH were significantly weaker than those of TIGIT - CD8 + T cells. However, in HCs, the difference in the SARS-CoV-2-specific responses induced between TIGIT + CD8 + T cells and TIGIT - CD8 + T cells was insignificant at 4W and 12W, except at 0W. CONCLUSIONS TIGIT expression on CD8 + T cells may hinder the T-cell immune response to a booster dose of an inactivated SARS-CoV-2 vaccine, suggesting weakened resistance to SARS-CoV-2 infection, especially in PLWH. Furthermore, TIGIT may be used as a potential target to increase the production of SARS-CoV-2-specific CD8 + T cells, thereby enhancing the effectiveness of vaccination.
Humans ; Antibodies, Viral ; CD8-Positive T-Lymphocytes ; COVID-19/complications* ; COVID-19 Vaccines/immunology* ; HIV Infections/complications* ; Receptors, Immunologic ; SARS-CoV-2