Catalog No.	PA007380.m2b
Product Name	Anti-mouse CTLA-4 Monoclonal Antibody (Clone: 9D9) | PA007380.m2b
Supplier Name	Syd Labs, Inc.
Brand Name	Syd Labs
Synonyms	cytotoxic T-lymphocyte associated antigen 4, cytotoxic T-lymphocyte antigen 4, CD152, CTLA4
Summary	The in vivo grade recombinant mouse monoclonal antibody (clone: 9D9) specifically binds to the mouse CTLA-4 protein.
Clone	9D9
Isotype	Mouse IgG2b kappa
Specificity/Sensitivity	The in vivo grade recombinant mouse monoclonal antibody (clone: 9D9) specifically binds to the mouse CTLA-4 protein.
Applications	ELISA, flow cytometry, neutralization, functional assays such as bioanalytical PK and ADA assays, and those assays for studying biological pathways affected by the mouse CTLA-4 protein.
Form Of Antibody	0.2 uM filtered solution, pH 7.4, no stabilizers or preservatives.
Endotoxin	< 1 EU per 1 mg of the protein by the LAL method.
Purity	>95% by SDS-PAGE under reducing conditions.
Shipping	Anti-mouse CTLA-4 Monoclonal Antibody is shipped with ice pack. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage	Use a manual defrost freezer and avoid repeated freeze-thaw cycles. 12 months from date of receipt, -20 to -70°C as supplied. 1 month from date of receipt, 2 to 8°C as supplied.
Note	Recombinant mouse IgG2b isotype control, Recombinant mouse IgG2c LALAPG isotype control, and Recombinant mouse IgG2a LALAPG isotype control are available. Condition of sample preparation and optimal sample dilution should be determined experimentally by the investigator.
Order Offline	Phone: 1-617-401-8149 Fax: 1-617-606-5022 Email: message@sydlabs.com Or leave a message with a formal purchase order (PO) Or credit card.

Description

PA007380.m2b: Recombinant Anti-mouse CTLA-4 Monoclonal Antibody(Clone: 9D9) , Mouse IgG2b Kappa, In vivo Grade

The anti-mouse CTLA-4 monoclonal antibody (clone: 9D9) was produced in mammalian cells. The 9D9 antibody blocks the mouse cytotoxic T lymphocyte antigen-4 (CTLA-4). Blocking CTLA-4 removes an inhibitory signal from reducing the activity of T lymphocytes.

Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is an inhibitory molecule that competes with the stimulatory CD28 for binding to B7 on antigen presenting cells. CTLA-4 and CD28 are both presented on the surface of T-cells.

References for Anti-mouse CTLA-4:

1、Pulsatile MEK Inhibition Improves Anti-tumor Immunity and T Cell Function in Murine Kras Mutant Lung Cancer
Hyejin Choi,et al.Cell Rep. 2019.PMCID: PMC6719696
“KRAS is one of the driver oncogenes in non-small-cell lung cancer (NSCLC) but remains refractory to current modalities of targeted pathway inhibition, which include inhibiting downstream kinase MEK to circumvent KRAS activation. Here, we show that pulsatile, rather than continuous, treatment with MEK inhibitors (MEKis) maintains T cell activation and enables their proliferation. Two MEKis, selumetinib and trametinib, induce T cell activation with increased Anti-mouse CTLA-4 Antibody expression and, to a lesser extent, PD-1 expression on T cells in vivo after cyclical pulsatile MEKi treatment. In addition, the pulsatile dosing schedule alone shows superior anti-tumor effects and delays the emergence of drug resistance. Furthermore, pulsatile MEKi treatment combined with CTLA-4 blockade prolongs survival in mice bearing tumors with mutant Kras. Our results set the foundation and show the importance of a combinatorial therapeutic strategy using pulsatile targeted therapy together with immunotherapy to optimally enhance tumor delay and promote long-term anti-tumor immunity.”

2、Antigen receptor‐engineered Tregs inhibit CNS autoimmunity in cell therapy using nonredundant immune mechanisms in mice
Jelka Pohar,et al.Eur J Immunol. 2022.PMCID: PMC9542066
“CD4+FOXP3+ Tregs are currently explored to develop cell therapies against immune‐mediated disorders, with an increasing focus on antigen receptor‐engineered Tregs. Deciphering their mode of action is necessary to identify the strengths and limits of this approach. Here, we addressed this issue in an autoimmune disease of the CNS, EAE. Following disease induction, autoreactive Tregs upregulated LAG‐3 and Anti-mouse CTLA-4 Antibody in LNs, while IL‐10 and amphiregulin (AREG) were increased in CNS Tregs. Using genetic approaches, we demonstrated that IL‐10, CTLA‐4, and LAG‐3 were nonredundantly required for the protective function of antigen receptor‐engineered Tregs against EAE in cell therapy whereas AREG was dispensable. Treg‐derived IL‐10 and CTLA‐4 were both required to suppress acute autoreactive CD4+ T‐cell activation, which correlated with disease control. These molecules also affected the accumulation in the recipients of engineered Tregs themselves, underlying complex roles for these molecules. Noteworthy, despite the persistence of the transferred Tregs and their protective effect, autoreactive T cells eventually accumulated in the spleen of treated mice. In conclusion, this study highlights the remarkable power of antigen receptor‐engineered Tregs to appropriately provide multiple suppressive factors nonredundantly necessary to prevent autoimmune attacks.”

3、Adenovirus Encoded Adjuvant (AdEnA) anti-CTLA-4, a novel strategy to improve Adenovirus based vaccines against infectious diseases and cancer
Anna Morena D’Alise,et al.Anna Morena D’Alise. 2023.PMCID: PMC10169702
“Introduction
Virus vectored genetic vaccines (Vvgv) represent a promising approach for eliciting immune protection against infectious diseases and cancer. However, at variance with classical vaccines to date, no adjuvant has been combined with clinically approved genetic vaccines, possibly due to the detrimental effect of the adjuvant-induced innate response on the expression driven by the genetic vaccine vector. We reasoned that a potential novel approach to develop adjuvants for genetic vaccines would be to “synchronize” in time and space the activity of the adjuvant with that of the vaccine.
Methods
To this aim, we generated an Adenovirus vector encoding a murine anti-CTLA-4 monoclonal antibody (Ad-9D9) as a genetic adjuvant for Adenovirus based vaccines.”

4、Intradermal DNA vaccination combined with dual CTLA-4 and PD-1 blockade provides robust tumor immunity in murine melanoma
Spela Kos,et al.PLoS One. 2019.PMCID: PMC6544376
“We aimed to explore whether the combination of intradermal DNA vaccination, to boost immune response against melanoma antigens, and immune checkpoint blockade, to alleviate immunosuppression, improves antitumor effectiveness in a murine B16F10 melanoma tumor model. Compared to single treatments, a combination of intradermal DNA vaccination (ovalbumin or gp100 plasmid adjuvanted with IL12 plasmid) and immune checkpoint Anti-mouse CTLA-4 Antibody/PD-1 blockade resulted in a significant delay in tumor growth and prolonged survival of treated mice. Strong activation of the immune response induced by combined treatment resulted in a significant antigen-specific immune response, with elevated production of antigen-specific IgG antibodies and increased intratumoral CD8+ infiltration. These results indicate a potential application of the combined DNA vaccination and immune checkpoint blockade, specifically, to enhance the efficacy of DNA vaccines and to overcome the resistance to immune checkpoint inhibitors in certain cancer types.”

5、Synthetic DNA-encoded monoclonal antibody delivery of anti-CTLA-4 antibodies induces tumor shrinkage in vivo
Elizabeth K Duperret,et al.Cancer Res. 2019.PMCID: PMC6239932
“Antibody-based immune therapies targeting the T cell checkpoint molecules CTLA-4 and PD-1 have impacted cancer therapy. However, this immune therapy requires complex manufacturing and frequent dosing, limiting the global use of this treatment. Here we focused on the development of a DNA-encoded monoclonal antibody (DMAb) approach for delivery of anti-CTLA-4 monoclonal antibodies in vivo. With this technology, engineered and formulated DMAb plasmids encoding IgG inserts were directly injected into muscle and delivered intracellularly by electroporation, leading to in vivo expression and secretion of the encoded IgG. DMAb expression from a single dose can continue for several months without the need for repeated administration. Delivery of an optimized DMAb encoding anti-mouse CTLA-4 IgG resulted in high serum levels of the antibody as well as tumor regression in Sa1N and CT26 tumor models. DNA-delivery of the anti-human CTLA-4 antibodies ipilimumab and tremelimumab in mice achieved potent peak levels of approximately 85μg/mL and 58μg/mL, respectively. These DMAb exhibited prolonged expression, with maintenance of serum levels at or above 15μg/mL for over a year. Anti-human CTLA-4 DMAbs produced in vivo bound to human CTLA-4 protein expressed on stimulated human PBMC and induced T cell activation in a functional assay ex vivo. In summary, direct in vivo expression of DMAb encoding checkpoint inhibitors serve as a novel tool for immunotherapy that could significantly improve availability and provide broader access to such therapies.”

6、Reprogramming the Intrahepatic Cholangiocarcinoma Immune Microenvironment by Chemotherapy and CTLA-4 Blockade Enhances Anti–PD-1 Therapy
Jiang Chen,et al.Cancer Immunol Res. 2024.PMCID: PMC10985468
“Intrahepatic cholangiocarcinoma (ICC) has limited therapeutic options and a dismal prognosis. Adding blockade of the anti–programmed cell death protein (PD)-1 pathway to gemcitabine/cisplatin chemotherapy has recently shown efficacy in biliary tract cancers but with low response rates. Here, we studied the effects of anti–cytotoxic T lymphocyte antigen (CTLA)-4 when combined with anti–PD-1 and gemcitabine/cisplatin in orthotopic murine models of ICC. This combination therapy led to substantial survival benefits and reduction of morbidity in two aggressive ICC models that were resistant to immunotherapy alone. Gemcitabine/cisplatin treatment increased tumor-infiltrating lymphocytes and normalized the ICC vessels and, when combined with dual Anti-mouse CTLA-4 Antibody/PD-1 blockade, increased the number of activated CD8+Cxcr3+IFNγ+ T cells. CD8+ T cells were necessary for the therapeutic benefit because the efficacy was compromised when CD8+ T cells were depleted. Expression of Cxcr3 on CD8+ T cells is necessary and sufficient because CD8+ T cells from Cxcr3+/+ but not Cxcr3–/– mice rescued efficacy in T cell‒deficient mice. Finally, rational scheduling of anti–CTLA-4 “priming” with chemotherapy followed by anti–PD-1 therapy achieved equivalent efficacy with reduced overall drug exposure. These data suggest that this combination approach should be clinically tested to overcome resistance to current therapies in ICC patients.”

7、Selective FcγR Co-engagement on APCs Modulates the Activity of Therapeutic Antibodies Targeting T Cell Antigens
Jeremy D Waight,et al.Cancer Cell. 2018.PMCID: PMC6292441
“The co-engagement of fragment crystallizable (Fc) gamma receptors (FcγRs) with the Fc region of recombinant immunoglobulin monoclonal antibodies (mAbs) and its contribution to therapeutic activity has been extensively studied. For example, Fc-FcγR interactions have been shown to be important for mAb-directed effector cell activities, as well as mAb-dependent forward signaling into target cells via receptor clustering. Here we identify a function of mAbs targeting T cell-expressed antigens that involves FcγR co-engagement on antigen-presenting cells (APCs). In the case of mAbs targeting CTLA-4 and TIGIT, the interaction with FcγR on APCs enhanced antigen-specific T cell responses and tumoricidal activity. This mechanism extended to an anti-CD45RB mAb, which led to FcγR-dependent regulatory T cell expansion in mice.”

8、ICOS Costimulation at the Tumor Site in Combination with CTLA-4 Blockade Therapy Elicits Strong Tumor Immunity
Mario Martínez Soldevilla,et al.Mol Ther. 2019.PMCID: PMC6838990
“Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) blockade therapy is able to induce long-lasting antitumor responses in a fraction of cancer patients. Nonetheless, there is still room for improvement in the quest for new therapeutic combinations. ICOS costimulation has been underscored as a possible target to include with CTLA-4 blocking treatment. Herein, we describe an ICOS agonistic aptamer that potentiates T cell activation and induces stronger antitumor responses when locally injected at the tumor site in combination with anti-CTLA-4 antibody in different tumor models. Furthermore, ICOS agonistic aptamer was engineered as a bi-specific tumor-targeting aptamer to reach any disseminated tumor lesions after systemic injection. Treatment with the bi-specific aptamer in combination with CTLA-4 blockade showed strong antitumor immunity, even in a melanoma tumor model where CTLA-4 treatment alone did not display any significant therapeutic benefit. Thus, this work provides strong support for the development of combinatorial therapies involving anti-CTLA-4 blockade and ICOS agonist tumor-targeting agents.”

9、CTLA-4 suppresses hapten-induced contact hypersensitivity in atopic dermatitis model mice
Hiroe Tetsu,et al.Sci Rep. 2023.PMCID: PMC10188484
“Atopic dermatitis (AD) patients with skin barrier dysfunction are considered to be at a higher risk of allergic contact dermatitis (ACD), although previous studies showed that attenuated ACD responses to strong sensitizers in AD patients compared to healthy controls. However, the mechanisms of ACD response attenuation in AD patients are unclear. Therefore, using the contact hypersensitivity (CHS) mouse model, this study explored the differences in CHS responses to hapten sensitization between NC/Nga mice with or without AD induction (i.e., non-AD and AD mice, respectively). In this study, ear swelling and hapten-specific T cell proliferation were significantly lower in AD than in non-AD mice. Moreover, we examined the T cells expressing cytotoxic T lymphocyte antigen-4 (CTLA-4), which is known to suppress T cell activation, and found a higher frequency of CTLA-4+ regulatory T cells in draining lymph node cells in AD than in non-AD mice. Furthermore, the blockade of CTLA-4 using a monoclonal antibody eliminated the difference in ear swelling between non-AD and AD mice. These findings suggested that CTLA-4+T cells may contribute to suppressing the CHS responses in AD mice.”

10、Botensilimab, an Fc-Enhanced Anti–CTLA-4 Antibody, Is Effective against Tumors Poorly Responsive to Conventional Immunotherapy
Dhan Chand,et al.Cancer Discov. 2024.PMCID: PMC11609826
“Conventional immune checkpoint inhibitors (ICI) targeting cytotoxic T-lymphocyte antigen 4 (CTLA-4) elicit durable survival but primarily in patients with immune-inflamed tumors. Although the mechanisms underlying response to anti–CTLA-4 remain poorly understood, Fc-gamma receptor (FcγR) IIIA coengagement seems critical for activity, potentially explaining the modest clinical benefits of approved anti–CTLA-4 antibodies. We demonstrate that anti–CTLA-4 engineered for enhanced FcγR affinity leverages FcγR-dependent mechanisms to potentiate T-cell responsiveness, reduce intratumoral regulatory T cells, and enhance antigen-presenting cell activation. Fc-enhanced anti–CTLA-4 promoted superior efficacy in mouse models and remodeled innate and adaptive immunity versus conventional anti–CTLA-4. These findings extend to patients treated with botensilimab, an Fc-enhanced anti–CTLA-4 antibody, with clinical activity across multiple poorly immunogenic and ICI treatment–refractory cancers. Efficacy was independent of tumor neoantigen burden or FCGR3A genotype. However, FCGR2A and FCGR3A expression emerged as potential response biomarkers. These data highlight the therapeutic potential of Fc-enhanced anti–CTLA-4 antibodies in cancers unresponsive to conventional ICI therapy.”

11、Dual IL-6 and CTLA-4 blockade regresses pancreatic tumors in a T cell– and CXCR3-dependent manner
Michael Brandon Ware,et al.JCI Insight. 2023.PMCID: PMC10243806
“This study aimed to enhance antitumor immune responses to pancreatic cancer via Ab-based blockade of IL-6 and cytotoxic T-lymphocyte–associated protein 4 (CTLA-4). Mice bearing s.c. or orthotopic pancreatic tumors were treated with blocking Abs to IL‑6 and/or CTLA-4. In both tumor models, dual IL-6 and CTLA-4 blockade significantly inhibited tumor growth. Additional investigations revealed that dual therapy induced an overwhelming infiltration of T cells into the tumor as well as changes in CD4+ T cell subsets. Dual blockade therapy elicited CD4+ T cells to secrete increased IFN-γ in vitro. Likewise, in vitro stimulation of pancreatic tumor cells with IFN-γ profoundly increased tumor cell production of CXCR3-specific chemokines, even in the presence of IL-6. In vivo blockade of CXCR3 prevented orthotopic tumor regression in the presence of the combination treatment, demonstrating a dependence on the CXCR3 axis for antitumor efficacy. Both CD4+ and CD8+ T cells were required for the antitumor activity of this combination therapy, as their in vivo depletion via Abs impaired outcomes. These data represent the first report to our knowledge of IL-6 and CTLA‑4 blockade as a means to regress pancreatic tumors with defined operative mechanisms of efficacy.”

12、TLR9 activation cooperates with T cell checkpoint blockade to regress poorly immunogenic melanoma
Matthew J Reilley,et al.J Immunother Cancer. 2019.PMCID: PMC6880482
“Tumors that lack pre-existing immune infiltration respond poorly to T cell checkpoint blockade immunotherapy. These cancers often surround themselves with high densities of suppressive myeloid stroma while excluding immunostimulatory dendritic cells. Tumor-resident myeloid cells and selected lymphocyte populations retain expression of Toll-like Receptors (TLR) that sense common features of pathogens and activate innate immunity in response. We explored whether agonists of TLR9 could augment innate immunity to promote tumor regression alone or in combination with T cell checkpoint blockade. In the setting of the immunogenic B16-Ova (Ovalbumin) expressing melanoma model, local injection of the CpG oligonucleotide TLR9 agonist ODN1826 combined with systemic CTLA-4 blockade cured 45% of mice of both their treated and an untreated tumor on the opposite flank demonstrating the synergistic potential of this combination. Next, in the non-immunogenic B16-F10 melanoma model, we showed that only intra-tumoral, but not systemic TLR9 activation augments the therapeutic potential of checkpoint blockade. In this setting, intra-tumoral TLR9 activation cooperated equally with either CTLA-4 or PD-1 blockade co-administered locally or given systemically; however, the uninjected tumor rarely regressed. Anti-CTLA-4 combinations were associated with improved intra-tumoral CD8 to regulatory T cell ratios, while anti-PD-1 combinations elicited improved ratios of CD8 T cells relative to suppressive myeloid stroma. Using both a TLR9 agonist (MGN1703) and a CTLA-4 antibody (9D9-IgG2a) of increased potency cured 50% of bi-lateral B16-F10 melanoma. These findings suggest that intra-tumoral TLR9 agonists can improve sensitivity of poorly immunogenic tumors to T cell checkpoint blockade, and that newer, higher potency TLR agonists and checkpoint antibodies can raise the therapeutic ceiling for this combination therapy.”

13、CTLA-4 blockade drives loss of Treg stability in glycolysis-low tumors
Roberta Zappasodi,et al.Nature. 2021.PMCID: PMC8057670
“Limiting the metabolic competition in the tumor microenvironment (TME) may increase the effectiveness of immunotherapy. Because of its critical role in glucose metabolism of activated T cells, CD28 signaling has been proposed as a T-cell metabolic biosensor1. Conversely, CTLA-4 engagement has been shown to down-regulate T-cell glycolysis1. Here, we investigated the impact of CTLA-4 blockade on the metabolic fitness of intra-tumor T cells in relationship to the tumor glycolytic capacity. We found that CTLA-4 blockade promotes immune cell infiltration and metabolic fitness especially in glycolysis-low tumors. Accordingly, anti-CTLA-4 achieved better therapeutic outcomes in mice bearing glycolysis-defective tumors. Intriguingly, tumor-specific CD8+ T-cell responses correlated with phenotypic and functional destabilization of tumor-infiltrating regulatory T cells (Tregs) toward IFN-γ- and TNF-α-producing cells in glycolysis-defective tumors. By mimicking the highly and poorly glycolytic TME in vitro, we show that the effect of CTLA-4 blockade to promote Treg destabilization is dependent on Treg glycolysis and CD28 signaling. These findings indicate that decreasing tumor competition for glucose may facilitate the therapeutic activity of CTLA-4 blockade, thus supporting its combination with inhibitors of tumor glycolysis. Moreover, these results reveal a new mechanism through which anti-CTLA-4 interferes with Treg function in the presence of glucose.”

14、Fc-independent functions of anti-CTLA-4 antibodies contribute to anti-tumor efficacy
Yosuke Sato,et al.Cancer Immunol Immunother. 2022.PMCID: PMC9463231
“Ipilimumab, a monoclonal antibody that recognizes cytotoxic T-lymphocyte associated protein 4 (CTLA-4), was the first immune checkpoint inhibitor approved by the FDA to treat metastatic melanoma patients. Multiple preclinical studies have proposed that Fc effector functions of anti-CTLA-4 therapy are required for anti-tumor efficacy, in part, through the depletion of intratumoral regulatory T cells (Tregs). However, the contribution of the Fc-independent functions of anti-CTLA-4 antibodies to the observed efficacy is not fully understood. H11, a non-Fc-containing single-domain antibody (VHH) against CTLA-4, has previously been demonstrated to block CTLA-4-ligand interaction. However, in vivo studies demonstrated lack of anti-tumor efficacy with H11 treatment. Here, we show that a half-life extended H11 (H11-HLE), despite the lack of Fc effector functions, induced potent anti-tumor efficacy in mouse syngeneic tumor models. In addition, a non-Fc receptor binding version of ipilimumab (Ipi-LALAPG) also demonstrated anti-tumor activity in the absence of Treg depletion. Thus, we demonstrate that Fc-independent functions of anti-CTLA-4 antibodies contributed to anti-tumor efficacy, which may indicate that non-Treg depleting activity of anti-CTLA-4 therapy could benefit cancer patients in the clinic..”

15、Prophylactic IL-23 blockade uncouples efficacy and toxicity in dual CTLA-4 and PD-1 immunotherapy
Mingyi Ju,et al.J Immunother Cancer. 2024.PMCID: PMC11293404
“Background
Immune-related adverse events (irAEs), characterized by targeted inflammation, occur in up to 60% of patients with melanoma treated with immune checkpoint inhibitors (ICIs). Evidence proved that the baseline peripheral blood profiles of patients at risk for severe irAEs development paralleled clinical autoimmunity. Interleukin (IL)-23 blockade with risankizumab is recommended for cases that are suffering from autoimmune disease, such as autoimmune colitis. However, currently, the role of IL-23 in irAEs onset and severity remains poorly understood.
Methods
The pro-inflammatory cytokines most associated with severe irAEs onset were identified by retrospective analysis based on GSE186143 data set. To investigate the efficacy of prophylactic IL-23 blockade administration to prevent irAEs, refer to a previous study, we constructed two irAEs murine models, including dextran sulfate sodium salt (DSS)-induced colitis murine model and a combined-ICIs-induced irAEs murine model. To further explore the applicability of our findings, murine models with graft-versus-host disease were established, in which Rag2−/−Il2rg−/− mice were transferred with human peripheral blood mononuclear cells and received combined cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) and programmed cell death protein-1 (PD-1) treatment. Human melanoma cells were xenografted into these mice concomitantly.”

16、The CTLA-4 x OX40 bispecific antibody ATOR-1015 induces anti-tumor effects through tumor-directed immune activation
Anne Månsson Kvarnhammar,et al.J Immunother Cancer. 2019.PMCID: PMC6458634
“Background
The CTLA-4 blocking antibody ipilimumab has demonstrated substantial and durable effects in patients with melanoma. While CTLA-4 therapy, both as monotherapy and in combination with PD-1 targeting therapies, has great potential in many indications, the toxicities of the current treatment regimens may limit their use. Thus, there is a medical need for new CTLA-4 targeting therapies with improved benefit-risk profile.
Methods
ATOR-1015 is a human CTLA-4 x OX40 targeting IgG1 bispecific antibody generated by linking an optimized version of the Ig-like V-type domain of human CD86, a natural CTLA-4 ligand, to an agonistic OX40 antibody. In vitro evaluation of T-cell activation and T regulatory cell (Treg) depletion was performed using purified cells from healthy human donors or cell lines. In vivo anti-tumor responses were studied using human OX40 transgenic (knock-in) mice with established syngeneic tumors. Tumors and spleens from treated mice were analyzed for CD8+ T cell and Treg frequencies, T-cell activation markers and tumor localization using flow cytometry.”

17、Inhibition of immune checkpoints PD-1, CTLA-4, and IDO1 coordinately induces immune-mediated liver injury in mice
Timothy Affolter,et al.PLoS One. 2019.PMCID: PMC6528985
“Cancer cells harness immune checkpoints such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1) and indoleamine 2,3-dioxygenase 1 (IDO1) to evade immune control. Checkpoint inhibitors have demonstrated durable anti-tumor efficacy in human and preclinical models. Liver toxicity is one of the common immune-related adverse events associated with checkpoint inhibitors (CPIs) and its frequency and severity often increase significantly during CPI combination therapies. We aim to develop a mouse model to elucidate the immune mechanisms of CPI-associated liver toxicity. Co-administration of CTLA-4 blocking antibody, 9D9, and/or an IDO1 inhibitor, epacadostat in wild-type and PD-1-/- mice (to simulate the effect of PD1 blockade) synergistically induced liver injury and immune cell infiltration. Infiltrated cells were primarily composed of CD8+ T cells and positively associated with hepatocyte necrosis. Strikingly, sites of hepatocyte necrosis were frequently surrounded by clusters of mononuclear immune cells. CPI treatments resulted in increased expression of genes associated with hepatocyte cell death, leukocyte migration and T cell activation in the liver. In conclusion, blockade of immune checkpoints PD-1, CTLA-4, and IDO1 act synergistically to enhance T cell infiltration and activity in the liver, leading to hepatocyte death.”

18、A reappraisal of CTLA-4 checkpoint blockade in cancer immunotherapy
Xuexiang Du,et al.Cell Res. 2018.PMCID: PMC5939050
“It is assumed that anti-CTLA-4 antibodies cause tumor rejection by blocking negative signaling from B7-CTLA-4 interactions. Surprisingly, at concentrations considerably higher than plasma levels achieved by clinically effective dosing, the anti-CTLA-4 antibody Ipilimumab blocks neither B7 trans-endocytosis by CTLA-4 nor CTLA-4 binding to immobilized or cell-associated B7. Consequently, Ipilimumab does not increase B7 on dendritic cells (DCs) from either CTLA4 gene humanized (Ctla4h/h) or human CD34+ stem cell-reconstituted NSG™ mice. In Ctla4h/m mice expressing both human and mouse CTLA4 genes, anti-CTLA-4 antibodies that bind to human but not mouse CTLA-4 efficiently induce Treg depletion and Fc receptor-dependent tumor rejection. The blocking antibody L3D10 is comparable to the non-blocking Ipilimumab in causing tumor rejection. Remarkably, L3D10 progenies that lose blocking activity during humanization remain fully competent in inducing Treg depletion and tumor rejection. Anti-B7 antibodies that effectively block CD4 T cell activation and de novo CD8 T cell priming in lymphoid organs do not negatively affect the immunotherapeutic effect of Ipilimumab. Thus, clinically effective anti-CTLA-4 mAb causes tumor rejection by mechanisms that are independent of checkpoint blockade but dependent on the host Fc receptor. Our data call for a reappraisal of the CTLA-4 checkpoint blockade hypothesis and provide new insights for the next generation of safe and effective anti-CTLA-4 mAbs.”

19、Leukemic B Cell CTLA-4 Suppresses Co-stimulation of T cells
Priscilla Do,et al.J Immunol. 2020.PMCID: PMC6478536
“Clinical benefit of CTLA-4 blockade on T cells is known, yet the impact of its expression on cancer cells remains unaddressed. We define an immunosuppressive role for tumor expressed CTLA-4 using chronic lymphocytic leukemia (CLL) as a disease model. CLL, among other cancer cells, are CTLA-4+. Co-culture with activated human T cells induced surface CTLA-4 on primary human CLL B cells. CTLA-4 on CLL-derived human cell lines decreased CD80 expression on co-cultured CD80+ cells, with restoration upon CTLA-4 blockade. Co-culture of CTLA-4+ CLL cells with CD80-GFP+ cell lines revealed transfer of CD80-GFP into CLL tumor cells, similar to CTLA-4+ T cells able to trans-endocytose CD80. Co-culture of T cells with CTLA-4+ CLL cells decreased IL2 production. Using a human CTLA-4 knock-in mouse lacking FcγR function, anti-tumor efficacy was observed by blocking murine CTLA-4 on tumor cells in isolation of the T cell effect and Fc-mediated depletion. These data implicate tumor CTLA-4 in cancer cell-mediated immunosuppression in vitro and to have a functional role on tumor cells in vivo.”

20、Activity of murine surrogate antibodies for durvalumab and tremelimumab lacking effector function and the ability to deplete regulatory T cells in mouse models of cancer
Darren J Schofield,et al.MAbs. 2021.PMCID: PMC7831362
“Preclinical studies of PD-L1 and CTLA-4 blockade have relied heavily on mouse syngeneic tumor models with intact immune systems, which facilitate dissection of immunosuppressive mechanisms in the tumor microenvironment. Commercially developed monoclonal antibodies (mAbs) targeting human PD-L1, PD-1, and CTLA-4 may not demonstrate cross-reactive binding to their mouse orthologs, and surrogate anti-mouse antibodies are often used in their place to inhibit these immune checkpoints. In each case, multiple choices exist for surrogate antibodies, which differ with respect to species of origin, affinity, and effector function. To develop relevant murine surrogate antibodies for the anti-human PD-L1 mAb durvalumab and the anti-human CTLA-4 mAb tremelimumab, rat/mouse chimeric or fully murine mAbs engineered for reduced effector function were developed and compared with durvalumab and tremelimumab. Characterization included determination of target affinity, in vivo effector function, pharmacokinetic profile, and anti-tumor efficacy in mouse syngeneic tumor models. Results showed that anti–PD-L1 and anti–CTLA-4 murine surrogates with pharmacologic properties similar to those of durvalumab and tremelimumab demonstrated anti-tumor activity in a subset of commonly used mouse syngeneic tumor models. This activity was not entirely dependent on antibody-dependent cellular cytotoxicity, antibody-dependent cellular phagocytosis effector function, or regulatory T-cell depletion, as antibodies engineered to lack these features showed activity in models historically sensitive to checkpoint inhibition, albeit at a significantly lower level than antibodies with intact effector function.”

Related Recombinant IgG Reference Antibodies:

Recombinant mouse lgG2b isotype control antibody
Recombinant mouse IgG2c LALAPG isotype control antibody
Recombinant mouse IgG2a LALAPG isotype control antibody

Syd Labs provides the following research grade anti-CTLA-4 antibody biosimilars:

Ipilimumab Biosimilar, research grade, anti-human CTLA-4 monoclonal antibody
Tremelimumab Biosimilar, research grade, anti-human CTLA-4 monoclonal antibody

Recombinant CTLA-4 Proteins:

Biotinylated Human CTLA-4 Protein
Cynomolgus CTLA-4 Protein
Human CTLA-4 Protein

Anti-mouse CTLA-4 Antibody(Clone: 9D9) from: Anti-mouse CTLA-4 Monoclonal Antibody, Mouse IgG2b Kappa (Clone: 9D9): PA007380.m2b Syd Labs