Cloning and identification of the CTLA-4IgV gene and functional application of vaccine in Xinjiang sheep.

The new quest in CTLA-4 insufficiency: How to immune modulate effectively?

The costimulatory molecules B7-1 and B7-2 regulate T lymphocyte activation by delivering activating signals through CD28 and inhibitory signals through cytotoxic T lymphocyte-associated antigen 4 (CTLA-4). The importance of CTLA-4-mediated inhibition was demonstrated by the uncontrolled T cell activation and lymphoproliferative disease that develops in CTLA-4-deficient (-/-) mice. To examine the role of B7 signaling in the activation of CTLA-4-deficient T cells, we bred CTLA-4(-/-) mice with mice lacking B7-1, B7-2, or both B7 molecules. The CTLA-4/B7-1(-/-) and the CTLA-4/B7-2(-/-) mice develop lymphoproliferation and enhanced T cell activation. Mice lacking CTLA-4, B7-1, and B7-2 have a normal life-span, and do not have lymphocytic infiltrates in any organs, or increased T cell activation. Therefore, the two B7 molecules have overlapping functions, since either B7-1 or B7-2 alone can cause the CTLA-4(-/-) phenotype. Elimination of both B7-1 and B7-2 from the CTLA-4- deficient mouse abrogates the lymphocyte activation and disease, and does not reveal evidence for additional stimulatory CD28 ligands. The CTLA-4(-/-) phenotype can be reproduced with anti-CD28 antibody in mice lacking CTLA-4, B7-1, and B7-2, but wild-type mice are unaffected by the same treatment. This suggests that the inhibitory function of CTLA-4 can overcome strong CD28-mediated signaling in vivo.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) plays a critical role in down-regulating T cell responses. A number of autoimmune diseases have shown genetic linkage to the CTLA4 locus. We have cloned and expressed an alternatively spliced form of CTLA4 that has genetic linkage with type 1 diabetes in NOD mice. This splice variant of CTLA4, named ligand-independent CTLA4 (liCTLA4), lacks exon 2 including the MYPPPY motif essential for binding to the costimulatory ligands B7-1 and B7-2. liCTLA4 is expressed as a protein in primary T cells and strongly inhibits T cell responses by binding and dephosphorylating the TcRzeta chain. Expression of liCTLA4, but not full length CTLA4 (flCTLA4), was higher in memory/regulatory T cells from diabetes resistant NOD congenic mice compared to susceptible NOD mice. Transgenic expression of liCTLA4 in autoimmune prone Ctla4 -/- mice inhibited spontaneous T cell activation and prevented early lethality in the Ctla4 -/- mice. Thus, increased expression and negative signalling delivered by the liCTLA4 may play a critical role in regulating the development of T cell-mediated autoimmune diseases.

Immunotherapy at Large: Balancing tumor immunity and inflammatory pathology

Objective: To investigate the survival and death risk factors of mesothelioma cases stratified by the expression levels of CD8 and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) , providing new clue to evaluate disease progression and clinical outcome. Methods: This was a retrospective case report, which included 47 clinically and pathologically confirmed mesothelioma cases on November 2016. Their clinical and pathological information, asbestos exposure history and survival data were collected. Infiltrated lymphocyte, 5-methylcytosine (5-mC) , CTLA-4, CD8 and Ki-67 antigen were detected using hematoxylin-eosin staining and immunohistochemistry. Survival time and death risk factors of mesothelioma patients with different CD8 and CTLA-4 protein expression characteristics were analyzed. And analyze the influence of Ki-67 expression on the survival of patients with different CD8 and CTLA-4 protein and gene expression characteristics. Results: Among the 47 cases, 63.8% (30/47) had low/medium level of infiltrated lymphocyte. The immunohistochemistry scores of CTLA-4, CD8, 5-mC and Ki-67 were 92.97 (54.95, 120.65) , 72.41 (36.62, 89.82) , 11.09 (3.40, 52.89) and 5.88 (2.41, 11.48) , respectively. Patients with CD8(high) CTLA-4(high) had higher 5-mC level than those with CD8(high) CTLA-4(low) (P<0.01) . The median survival time of 27 cases was 0.83±0.29 year. The median survival times of those with CD8(high) CTLA-4(high) and CD8(high) CTLA-4(low) were 0.58±0.51 year and 0.83±0.30 year, respectively (P=0.521) . The immunohistochemistry score of Ki-67 ≥5.88 was an independent death risk factor for patients with CD8(high) CTLA-4(low) (HR=8.40, P=0.01) . Under different CD8 and CTLA-4 protein expression characteristics, in the patients with CD8(high) CTLA-4(low), the median survival times of those with high and low Ki-67 expression were 0.57±0.11 years and 2.31±0.46 years, respectively (P<0.01) . Under different CD8 and CTLA-4 mRNA expression characteristics, in the patients with CD8(high) CTLA-4(low), the median survival times of those with high and low Ki-67 mRNA expression were 1.20±0.36 years and 3.38±0.43 years, respectively (P=0.018) . Conclusion: Mesothelioma case with high CD8 but low CTLA-4 content might coexist DNA hypomethylation. In the presence of high Ki-67 expression, their survival time appears to be shortened with increased death risk.

Recently, systemic administration of a human monoclonal antibody directed against cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) expressed on circulating T cells in patients with chronic lymphocytic leukaemia (CLL) has been considered. Also, CLL cells have been shown to express CTLA-4, increased levels of which in the leukaemic compartment are a predictor of good clinical outcome. Since both CLL and Treg microenvironment cells can be targeted by the CTLA-4 blocking antibody in this immunotherapy approach, the investigation of the functional effect of CTLA-4 blockade on CLL cells might be of potential clinical relevance. The main aim of this study was to examine the effect of CTLA-4 blockade on proliferation activity and apoptosis of CLL cells in patients with low and high CTLA-4 expression. We found that in the high CTLA-4-expressing CLL group, CTLA-4 blockade on the CLL cell surface resulted in a significant increase in the median percentages of Ki67+ cells and a tendency to decrease in the proportion of apoptotic cells. In contrast, in the low CTLA-4 expressors, CTLA-4 blockade did not affect the proliferation activity or the frequency of apoptosis. This study reports for the first time the different effect of CTLA-4 blockade on CLL cells in CLL patients depending on the levels of CTLA-4 expression. CTLA-4 blockade seems to induce pro-survival signals in leukaemic cells from CLL patients exhibiting high CTLA-4 expression, suggesting that an immunotherapy approach based on the systemic use of monoclonal anti-CTLA-4 antibodies could be an unfavourable strategy for some CLL patients.

Characterization of oligomers induced by inverse agonists of CTLA-4

Virus-specific cluster of differentiation 8 (CD8+) cytotoxic T cells (CTL) recognize viral antigens presented on major histocompatibility complex (MHC) class I chains on infected hepatocytes, with help from CD4+ T cells. However, this CTL response is frequently weak or undetectable in patients with chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infection. Programmed cell death 1 (PD-1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) are receptors in the CD28 family of costimulatory molecules, providing inhibitory signals to T cells. The overexpressions of PD-1 and CTLA-4 in patients with viral infection have been shown to associate with functional impairment of virus-specific T cells. In acute viral hepatitis, PD-1 and CTLA-4 are up-regulated during the symptomatic phase, and then down-regulated after recovery. These findings suggest that PD-1 and CTLA-4 have protective effects as inhibitory molecules to suppress cytotoxic T cells which induce harmful destruction of viral infected hepatocytes in self-limited viral hepatitis. In chronic viral hepatitis, the extended upregulations of PD-1 and CTLA-4 are associated with T cell exhaustion and persistent viral infection, suggesting positive correlations between expression of immune inhibitory factors and the chronicity of viral disease. In this review, we summarize recent literature relating to PD-1, CTLA-4, and other inhibitory receptors in antigen-specific T cell exhaustion in viral hepatitis, including hepatitis A, B, C, and others.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is a critical inhibitory checkpoint molecule, and monoclonal antibodies (mAbs) targeting CTLA-4 that restore anti-tumor T cell immunity have achieved clinical success. Here, we report a humanized IgG1 mAb, namely JS007, with high binding affinity to CTLA-4. JS007 shows superior binding affinity and T-cell activating efficiency over ipilimumab. Moreover, it demonstrates substantial in vivo tumor suppression efficacy at low doses. The crystal structure of JS007/CTLA-4 complex (PDB: 8HIT) shows JS007 adopts a heavy-chain-dominant binding mode, and mainly contacts the BC loop, DE loop and FG loop of CTLA-4. Notably, two Tyr residues (VH-Y100 and VL-Y32) from the complementarity-determining region loops insert into the two cavities formed by the residues from the loops of CTLA-4, which may contribute to the stabilization of the binding. Comparative analysis with other anti-CTLA-4 mAbs indicates that the double “wedge-into-hole” binding mode is unique for JS007 and may be responsible for the high-affinity binding to CTLA-4. These findings have provided an important molecular understanding of the high-affinity CTLA-4 blockade mAbs and shed light on future development of agents targeting CTLA-4.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) is an important negative regulator of T-cell response and its genetic association with type 1 diabetes (T1D) has recently been demonstrated. The frequent co-association of autoimmune diseases (AID) and the implication from multiple genome scans that the CTLA4 gene region is a general autoimmune region, led us to study the role of CTLA4 in independent cohorts of T1D, coeliac disease (CD) and rheumatoid arthritis (RA) patients. We present independent data that confirm the association of CTLA4 in Dutch patients with juvenile onset T1D and show differential association of CTLA4 with CD and RA. The CTLA4 gene polymorphisms were tested for association in 350 T1D, 310 CD, 520 RA patients and 900 controls. In addition, 218 families were tested by the transmission disequilibrium test (TDT). T1D patients showed the highest association with the MH30*G: -1147*C: +49*G: CT60*G: JO37_3*G (haplotype 2) in both a case/control cohort (P=0.002, OR=1.42) and by TDT (P=0.02, OR=1.43). In contrast, this haplotype showed no association in the RA and CD cohorts. However, we observed an increased frequency of the MH30*G: -1147*T: +49*A: CT60*G: JO37_3*A (haplotype 3) in the CD patients diagnosed at a young age (OR=1.6, P=0.026, P (c)=0.052). Furthermore, when T1D and CD patients were stratified based on the HLA risk, the T1D susceptible CTLA4 haplotype 2 was over-represented in the high HLA-risk T1D and CD groups. In conclusion, we confirmed association between CTLA4 haplotype 2 and T1D in the Dutch population. Association with another CTLA4 haplotype (haplotype 3) was confirmed for CD, but only in those patients who had an early age of expression. No effect was found between RA and CTLA4. The association of the CTLA4 haplotype 2 with the high-risk HLA genotype in T1D and CD, which share DQ2 as the one of high-risk alleles, might provide a clue to understanding the common genetic background of AID.

可以说是十年磨一剑,上海医药工业研究院亚东药业公司宝山药厂终于向社会正式推出其新产品——益公·肤康片、霜(即积雪甙片、霜。“益公”为其商标)。对于不幸受创伤、溃疡、硬皮病、疤痕等之苦的病友而言,这是一大喜讯。益公·肤康片、霜的有效成分是从传统中药中提取,经精制、加工所得。追本溯源可以知道,祖国医学于二千多年前就已开始用这些中药内服外治,汉代即载入《神农本草

Cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) was first discovered in 1987 and confirmed to be a protein that is mainly expressed on the surface of activated lymphocytes. CTLA-4 is expressed on the surface of T cells and binds to B7 expressed on antigen presenting cells(APCs) to potentially play a role in inhibiting lymphocyte proliferation. Inhibitors of CTLA-4 were developed to promote the anti-tumor effects of T cells and inhibit tumor growth. CTLA-4, as an immune checkpoint, has been realized as an important therapeutic target in bladder cancer. Two main CTLA-4 inhibitors are currently used: ipilimumab is a first-generation IgG1 monoclonal antibody that targets CTLA-4, and it is completely synthetic; tremelimumab, representing another class of CTLA-4 inhibitors, is a monoclonal antibody against CTLA-4 that acts similarly to ipilimumab and binds specifically to CTLA-4. The two types of CTLA-4 inhibitors were found to improve the treatment effect in patients with bladder cancer in comparison to conventional agents. To review this topic, we searched recently published related articles.

The recurrence rate of lymphoma is very high, and tumor stem cells may be an important mechanism. Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) can inhibit antitumor immunity and promote cancer progression, but its role and mechanism in lymphoma are still unclear. Here we collected lymphoma tissue and peripheral blood from patients with diffuse large B-cell lymphoma (DLBCL). Results showed that CTLA-4 expression and CD44+ cell in the high-risk group were significantly higher than that in the low-risk group. Correlation analysis showed that CTLA-4 expression positively correlated with CD44+ cell in lymphoma tissue and regulatory T (Treg) cells in lymphocytes. In vitro experiment showed that CTLA-4 increased the ratio of lymphoma stem cells, and proliferation and invasion of lymphoma cells through TGF-β pathway. Moreover, CTLA-4 enhanced the proliferation of Treg cells induced by lymphoma cells. Animal experiments showed that CTLA-4 can promote transplanted lymphoma growth. Immunohistochemistry results showed that both Ki-67 and CD44+ cells increased significantly in the CTLA-4 group. TGF-β neutralization can significantly block these effects of CTLA-4. In conclusion, CTLA-4 promoted DLBCL progression through lymphoma stem cell enrichment and immunosuppression.

Targeted treatment of immune thrombocytopenia in CTLA-4 insufficiency: a case report.

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) regulation represents a significant therapeutic target in addressing regulatory T cell (Treg) dysfunction and enhancing immune responses within the tumor microenvironment (TME). This study aimed to evaluate the inhibitory effect of compounds of Cyperus rotundus&nbsp;against the immune checkpoint CTLA-4 in silico. Compounds from Cyperus rotundus&nbsp;tubers were identified by Liquid Chromatography-High Resolution Mass Spectrometry (LC-HRMS). The compounds’ toxicity was predicted using Protox 3.0 web server. In silico&nbsp;study was performed using molecular docking and dynamics simulations of the compounds with CTLA-4 (PDB ID: 1I8L) protein using PyRx and YASARA softwares, respectively. Fourteen compounds were identified in Cyperus rotundus tubers.&nbsp;All compounds&nbsp;were classified as safe with LD50&nbsp;value ranging from 740 to 26000 mg/kg. Molecular docking showed Verbascoside A and Maltopentaose as potential inhibitors of CTLA-4 with binding energies of -6.3 and -5.4 Kcal/mol, respectively. In the molecular dynamics simulation, RMSD values of all complexes exceeded 3 Å, indicating instability. However, the backbone RMSD and ligand conformation RMSD of CTLA4-Verbascoside A with values below 3 Å indicated more stability. Meanwhile, the CTLA4-maltopentaose complex exhibited higher RMSD value, indicating a change in the CTLA-4 protein structure when interacting with maltopentaose. Furthermore, the prediction of protein targets of maltopentaose and verbascoside A revealed potential direct and indirect target proteins related to cancer signaling pathways, namely; PI3K-Akt and estrogen signaling pathways. The ability of these compounds to modulate the TME-related CTLA-4 indicates their potential as anticancer drug candidates.