Immune checkpoint inhibitors (ICIs), including anti-PD-1 and anti-CTLA-4 therapeutic agents, are now approved by the Food and Drug Administration for treatment of various types of cancer. However, the therapeutic efficacy of ICIs varies among patients and cancer types. Moreover, most patients do not develop durable antitumor responses after ICI therapy due to an ephemeral reversal of T-cell dysfunction. As co-stimulatory receptors play key roles in regulating the effector functions of T cells, activating co-stimulatory pathways may improve checkpoint inhibition efficacy, and lead to durable antitumor responses. Here, we review recent advances in our understating of co-stimulatory receptors in cancers, providing the necessary groundwork for the rational design of cancer immunotherapy.
Costimulatory and Inhibitory T-Cell Receptors ; Humans ; Immunotherapy ; T-Lymphocytes ; United States Food and Drug Administration

The study was aimed to detect the expressions of costimulatory molecules on CD3(+)CD4(+) T cells so as to accumulate informations for investigation of mechanism of myelodysplastic syndrome. 11 healthy blood donors as control and 38 patients with MDS de novo were studied. 38 MDS patients were divided into RA/RARS group and RAEB/RAEB-t group according to FAB classification. The expressions of CD28, CD154, CTLA-4, PD-1, CD25 on CD3(+)CD4(+) T cells in peripheral blood were detected by FCM. The results indicated that as compared with normal controls, the expression of CD28 in MDS patients decreased, and CD154 increased. The percentages of CTLA-4, PD-1 and CD25 in MDS were obviously higher than that in normal controls; the differences of CTLA-4, PD-1 and the ratio of CTLA-4/CD28 between RAEB/RAEB-t and RA/RARS were more significant with progressing of MDS. In conclusion, the expressions of costimulatory molecule in MDS patients were abnormal, which may be involved in the pathogenesis of MDS.
Adult ; Antigens, CD ; metabolism ; Apoptosis Regulatory Proteins ; metabolism ; CD28 Antigens ; metabolism ; CD40 Ligand ; metabolism ; CTLA-4 Antigen ; Case-Control Studies ; Female ; Humans ; Interleukin-2 Receptor alpha Subunit ; metabolism ; Lymphocyte Count ; Male ; Middle Aged ; Myelodysplastic Syndromes ; immunology ; metabolism ; Programmed Cell Death 1 Receptor ; T-Lymphocytes ; immunology ; metabolism ; Young Adult

Idiopathic thrombocytopenia purpura (ITP) is an autoimmune disease which is characterized by destruction of platelets by macrophages in the reticuloendothelial system. Recent studies suggest that ITP is related to the abnormal activation and apoptosis of T/B cells which lead to failure of immune tolerance. Now it is becoming clear that costimulatory signals are required for full T/B cell activation and assumed to modulate T/B cells responses as well as other aspects of the immune system. This review focuses on the role and state-of-the-art advancements of costimulatory signals in ITP.
Antigens, CD ; immunology ; Antigens, Differentiation ; immunology ; Antigens, Differentiation, T-Lymphocyte ; immunology ; B-Lymphocytes ; immunology ; CD28 Antigens ; immunology ; CTLA-4 Antigen ; Humans ; Immune Tolerance ; Inducible T-Cell Co-Stimulator Protein ; Purpura, Thrombocytopenic, Idiopathic ; immunology ; Receptors, Tumor Necrosis Factor ; immunology ; Signal Transduction ; physiology ; T-Lymphocytes ; immunology ; physiology

Bladder urothelial carcinoma(BUC)is a common malignant tumor in the urinary system.Pt-based chemotherapy has long been a standard therapeutic method for resectable or metastatic BUC,but with poor outcomes.Immune checkpoint inhibitors specific to programmed death 1(PD-1)/programmed death-ligand 1(PD-L1)and cytotoxic T lymphocyte-associated protein 4(CTLA-4)pathways have shown significant antitumor activities,safety,and enduring reactivity in clinical trials,thus creating a new epoch for the treatment of advanced-stage BUC.This article reviews the relationships of BUC with PD-1/PD-L1 and CTLA-4 pathways,as demonstrated in clinical trials.In particular,the authors elucidate the clinical studies on the application of immune checkpoint inhibitors in different BUC stages and their optimal combining strategies,with an attempt to improve the clinical use of immune inhibitors for BUC treatment.
Apoptosis ; B7-H1 Antigen ; CTLA-4 Antigen ; Immunotherapy ; Programmed Cell Death 1 Receptor ; Signal Transduction

BACKGROUNDThe transcription factor, repressor of GATA-3 (ROG), can simultaneously suppress the expression of T helper cells (Th1 and Th2) cytokines. Since the suppression of Th2 cytokines by GATA-3 is well understood, it is postulated that there are other molecular targets of ROG that can suppress the expression of the Th1 cytokines. We hypothesized that ROG might suppress the stimulators of T lymphocyte cytokines such as CD3, CD28, and inducible costimulator (ICOS), or indirectly enhance the expression of cytokine suppressors such as T lymphocyte-associated antigen-4 (CTLA-4) and CD45. The objective of this study was to clarify the molecular targets of ROG involved in suppressing Th1 or Th2 cytokines.

METHODSReal-time quantitative PCR (RT-PCR) and Western blotting were performed to evaluate the mRNA and protein levels of CD3, CD28, ICOS, CTLA-4, and CD45 in Th1 and Th2 cells during various levels of ROG expression. Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of interferon-γ (IFN-γ) and interleukin (IL)-4 in culture media of Th1 and Th2 cells.

RESULTSThe results showed that the mRNA and protein levels of ROG were relatively low in Th1 and Th2 cells (P < 0.01). After ROG-pcDNA3.1 transfection, the mRNA and protein level of ROG was significantly elevated, while the expression of ICOS, IFN-γ, and IL-4 was markedly down-regulated (P < 0.01). Conversely, transfection of ROG-siRNA led to inhibition of ROG expression and up-regulation of ICOS, IFN-γ and IL-4 (P < 0.01). However, the expression levels of CD3, CD28, CTLA-4 and CD45 did not change in either ROG-pcDNA3.1 or ROG-siRNA-transfected Th1 and Th2 cells (P > 0.05).

CONCLUSIONIt is concluded that ROG can inhibit the expression of Th1 and Th2 cytokines by down-regulating the expression of ICOS, which might be a potential molecular target for asthma treatment.

Animals ; Blotting, Western ; CD28 Antigens ; metabolism ; CD3 Complex ; metabolism ; CD4-Positive T-Lymphocytes ; metabolism ; CTLA-4 Antigen ; metabolism ; Cells, Cultured ; Cytokines ; metabolism ; Enzyme-Linked Immunosorbent Assay ; Inducible T-Cell Co-Stimulator Protein ; metabolism ; Interferon-gamma ; metabolism ; Interleukin-4 ; metabolism ; Leukocyte Common Antigens ; metabolism ; Male ; Mice ; Mice, Inbred BALB C ; Real-Time Polymerase Chain Reaction ; Repressor Proteins ; genetics ; metabolism ; T-Lymphocytes ; metabolism ; Th1 Cells ; metabolism ; Th2 Cells ; metabolism

CD28 family consists of CD28, ICOS, CTLA-4 and PD-1 molecules. The former two are activation receptors and the later two are inhibition receptors. They produce co-stimulatory signals combining with the relevant molecules in B7 family, which plays important role in T cell activation and homeostasis among T subsets. Although the mechanism of signaling by CD28 and CTLA-4 has been well studied, many questions still remain to be answered. Further investigations are required for substantiating the dual-signaling model.
Animals ; Antigens, CD ; Antigens, Differentiation ; immunology ; CD28 Antigens ; immunology ; CTLA-4 Antigen ; Humans ; Immunoglobulin Fc Fragments ; immunology ; Signal Transduction

Immunotherapy has become the mainstay for lung cancer treatment, providing sustained therapeutic responses and improved prognosis compared with those obtained with surgery, chemotherapy, radiotherapy, and targeted therapy. It has the potential for anti-tumor treatment and killing tumor cells by activating human immunity and has moved the targets of anti-cancer therapy from malignant tumor cells to immune cell subsets. Two kinds of immune checkpoints, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and programmed death-1 (PD-1)/programmed death ligand 1 (PD-L1), are the main targets of current immunotherapy in lung cancer. Despite the successful outcomes achieved by immune checkpoint inhibitors, a small portion of lung cancer patients remain unresponsive to checkpoint immunotherapy or may ultimately become resistant to these agents as a result of the complex immune modulatory network in the tumor microenvironment. Therefore, it is imperative to exploit novel immunotherapy targets to further expand the proportion of patients benefiting from immunotherapy. This review summarizes the molecular features, biological function, and clinical significance of several novel checkpoints that have important roles in lung cancer immune responses beyond the CTLA-4 and PD-1/PD-L1 axes, including the markers of co-inhibitory and co-stimulatory T lymphocyte pathways and inhibitory markers of macrophages and natural killer cells.
CTLA-4 Antigen ; Humans ; Immunotherapy ; Lung Neoplasms/therapy* ; Programmed Cell Death 1 Receptor ; T-Lymphocytes ; Tumor Microenvironment

OBJECTIVE: To investigate the expression of programmed death receptor-1 (PD-1) and inducible costimulator (ICOS) on the surface of CD8⁺ T cells in peripheral blood of patients with primary immune thrombocytopenia (ITP), and explore the roles of PD-1 and ICOS in the occurrence and development of ITP. METHODS: A total of 28 ITP patients treated in Tianjin Medical University General Hospital from September to December 2020 were selected, including 13 patients with newly diagnosed ITP, 15 patients with chronic ITP, and 22 healthy volunteers were recruited as control group. Flow cytometry was used to detect the expression levels of PD-1 and ICOS, and evaluate their correlation with clinical indicators. RESULTS: The percentage of CD8 ⁺ T cells in ITP patients of chronic group was higher than that of the newly diagnosed group and the control group (P<0.05). The expression level of PD-1 on CD8⁺ T cells in ITP patients of newly diagnosed group and chronic group were significantly lower than that of the control group (P<0.05), while the expression level of ICOS were significantly higher (P<0.05). In ITP patients, PD-1 was negatively correlated with platelet count (r=-0.4942, P<0.01), but positively with ICOS (r=0.4342). PD-1 and ICOS were both negatively correlated with lymphocyte count (r_PD-1=-0.4374; r_ICOS=-0.4492). CONCLUSION In ITP patients, the unbalanced expression of PD-1 and ICOS may interfere with the immune homeostasis of the body, which can be used as a therapeutic target for ITP patients.
CD8-Positive T-Lymphocytes/metabolism* ; Flow Cytometry ; Humans ; Inducible T-Cell Co-Stimulator Protein/metabolism* ; Platelet Count ; Programmed Cell Death 1 Receptor/metabolism* ; Purpura, Thrombocytopenic, Idiopathic

Immunotherapies based on immune checkpoint blockade (ICB) have significantly improved patient outcomes and offered new approaches to cancer therapy over the past decade. To date, immune checkpoint inhibitors (ICIs) of CTLA-4 and PD-1/PD-L1 represent the main class of immunotherapy. Blockade of CTLA-4 and PD-1/PD-L1 has shown remarkable efficacy in several specific types of cancers, however, a large subset of refractory patients presents poor responsiveness to ICB therapy; and the underlying mechanism remains elusive. Recently, numerous studies have revealed that metabolic reprogramming of tumor cells restrains immune responses by remodeling the tumor microenvironment (TME) with various products of metabolism, and combination therapies involving metabolic inhibitors and ICIs provide new approaches to cancer therapy. Nevertheless, a systematic summary is lacking regarding the manner by which different targetable metabolic pathways regulate immune checkpoints to overcome ICI resistance. Here, we demonstrate the generalized mechanism of targeting cancer metabolism at three crucial immune checkpoints (CTLA-4, PD-1, and PD-L1) to influence ICB therapy and propose potential combined immunotherapeutic strategies co-targeting tumor metabolic pathways and immune checkpoints.
Humans ; Antibodies, Monoclonal/pharmacology* ; B7-H1 Antigen/antagonists & inhibitors* ; CTLA-4 Antigen/antagonists & inhibitors* ; Immune Checkpoint Inhibitors/pharmacology* ; Neoplasms/drug therapy* ; Programmed Cell Death 1 Receptor ; Tumor Microenvironment

Immune checkpoint inhibitors (ICIs) have been used in treating a wide variety of cancers, but they challenge clinicians with a series of special immune related adverse events (irAEs) resulting from activated immune system. Since June 2018, when the first programmed cell death 1 (PD-1) inhibitor, nivolumab, was approved by the National Medical Products Administration (NMPA), abundant experience has been accumulated in coping with irAEs from PD-1 and PD-1 ligand 1 (PD-L1) blockade therapies. In October 2021, the first CTLA-4 inhibitor, ipilimumab, which has a different spectrum of irAEs was also approved by NMPA. The discrepancy in clinical features of pituitary irAEs is obvious between these two types of ICIs. Pituitary irAEs include hypophysitis and hypopituitarism. In this review of latest literature, we have summarized the incidence, possible mechanisms, time of onset, clinical presentations, hormone test, pituitary imaging, treatment strategies and recovery patterns of pituitary irAEs. By referring to domestic and foreign clinical guidelines, we have proposed practical suggestions for screening, diagnosing and treating pituitary irAEs.
Humans ; Immune Checkpoint Inhibitors/therapeutic use* ; Antibodies, Monoclonal/adverse effects* ; Programmed Cell Death 1 Receptor ; CTLA-4 Antigen ; Neoplasms/drug therapy*