Human CTLA-4 Quantikine HS ELISA Kit

• Reactivity: Hu
• Applications: ELISA
• Conjugate: HRP

Human CTLA-4 Quantikine HS ELISA Kit Summary

• Background: The Quantikine^TM HS Human CTLA-4 Immunoassay is a 4.0 hour solid-phase ELISA designed to measure human CTLA-4 in cell culture supernates, cell lysates, serum, plasma, and urine. It contains CHO cell-expressed recombinant human CTLA-4 and antibodies raised against the recombinant protein. Results obtained using natural human CTLA-4 showed linear curves that were parallel to the sta...ndard curves obtained using the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for natural human CTLA-4.
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• Specificity: Natural and recombinant human CTLA-4.
• Source: N/A
• Inter-Assay: See PDF Datasheet for details
• Intra-Assay: See PDF Datasheet for details
• Spike Recovery: See PDF Datasheet for details
• Sample Volume: See PDF Datasheet for details

Applications/Dilutions

• Dilutions:
  • ELISA
• Application Notes: No significant interference observed with available related molecules.

Packaging, Storage & Formulations

• Storage: Store the unopened product at 2 - 8 °C. Do not use past expiration date.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Human CTLA-4 Quantikine HS ELISA Kit

• CD
• CD152 antigen
• CD152
• CD152IDDM12
• CD28
• celiac disease 3
• CELIAC3
• CTLA4
• CTLA-4
• cytotoxic T-lymphocyte antigen 4
• cytotoxic T-lymphocyte protein 4
• Cytotoxic T-lymphocyte-associated antigen 4
• cytotoxic T-lymphocyte-associated protein 4
• cytotoxic T-lymphocyte-associated serine esterase-4
• GRD4
• GSE
• ICOS
• ligand and transmembrane spliced cytotoxic T lymphocyte associated antigen 4

Background

Cytotoxic T-Lymphocyte-Associated molecule-4 (CTLA-4), also known as cluster of differentiation 152 (CD152) is located on band q33-q34 on chromosome 2 in humans, and band C of chromosome 1 in mice (1). CTLA-4 has over 100 single nucleotide polymorphisms (SNPs) associated with autoimmunity and cancer. SNPs in the CTLA-4 promoter have been correlated with a variety of cancers including breast cancer, cervical cancer, colorectal cancer, head and neck cancer, hepatocellular cancer, melanoma, non-small-cell lung carcinoma (NSCLC), renal cancer and more. The 223 amino acid (aa) protein product consists of several domains including: a 36 aa leader peptide, a 116 aa extracellular Ig V-like ligand binding domain, a 37 aa transmembrane domain and a 34 aa cytoplasmic domain. The cytoplasmic domain contains tyrosine motifs, at Y201 VKM and Y218 FIP. Several intracellular proteins bind Y201 VKM including: phosphatidyl-inositol 3 kinase (PI3-K), Src homology 2 domain containing protein tyrosine phosphatase (SHP-2), the serine threonine phosphatase PP2a and clathrin adaptor proteins activator proteins (AP1, AP2).The mature type 1 transmembrane glycoprotein has a native molecular weight of 33-37 kDa (2,3). 

CTLA-4 plays a role in immune self-tolerance, which is important for avoiding autoimmune diseases. Unfortunately, this mechanism can be co-opted in order to suppress immune responses in the context of cancer. CTLA-4's highly studied role in the T cell response has been well described (4). CTLA-4 was originally identified as a gene that was specifically expressed by cytotoxic T lymphocytes. However, CTLA-4 transcripts have since been found in both T helper type 1 and 2 (Th1 and Th2) cells, and CD4+ and CD8+ T cell clones. CTLA-4 is a negative costimulatory molecule that is upregulated over the course of 2-3 days in T cells in response to T cell receptor (TCR) engagement with peptide major histocompatibility complex (pMHC) on antigen presenting cells. CTLA-4 recruitment to the immunological synapse is positively correlated with TCR signal strength. CTLA-4 outcompetes CD28, a positive costimulatory molecule, for the ligands B7-1 (CD80) and B7-2 (CD86) in order to attenuate T cell activation. CTLA-4 has a much higher affinity and avidity for B7-1 and B7-2 than CD28. CTLA-4 and CD28 are structurally homologous molecules that are members of the immunoglobulin (Ig) gene superfamily. CTLA-4 and CD28 are both expressed on the cell surface as disulfide-linked homodimers or as monomers. Unlike CTLA-4, CD28 expression is constitutive on the surfaces of 95% of CD4+ T cells and 50% of CD8+ T cells and is down regulated upon T cell activation. CTLA-4 negative co-stimulation suppresses T cell activation, thereby facilitating immune evasion. CTLA-4's effects occur via cell intrinsic and cell extrinsic mechanisms. Cell intrinsic mechanisms include inhibition of protein translation, recruitment of phosphatases, activation of ubiquitin ligases, inhibition of cytokine receptor signaling, and inhibition of lipid domain formation at membrane of T cells. Cell extrinsic mechanisms include stimulating the release of the suppressive indoleamine (2,3) deoxygenase (IDO), modulation of regulatory T cell function and the aforementioned competitive inhibition of CD28 costimulatory signaling (5). 

CTLA-4 is a well-known immune checkpoint target. The human monoclonal CTLA-4 antibody Ipilimumab was approved by the food and drug administration (FDA) to treat melanoma in 2011 (4). Since then, it has been approved for colorectal cancer in children 12 and older, hepatocellular carcinoma, NSCLC, and renal cell carcinoma. The Ipilimumab binding epitope overlaps with the B7 binding domain and blocks the interaction via steric hinderance of B7(4). Ipilimumab allows for B7-CD28 positive costimulatory signaling, which is an important signal for T cell activation (5).

Publications for CTLA-4 (HSCT40)(1)

Publication using HSCT40

• Darmadi, D;Lindarto, D;Siregar, J;Widyawati, T;Rusda, M;Amin, MM;Yusuf, F;Eyanoer, PC;Lubis, M;Rey, I; Factors affecting HBV DNA suppression in chronic hepatitis B patients treated with tenofovir disoproxil fumarate F1000Research 2023-08-24 [PMID: 37767077] (Human)

FAQs for CTLA-4 (HSCT40). (Showing 1 - 1 of 1 FAQ).

1. What is the difference between the Quantikine and Duoset ELISA kits?
   • Our Quantikine kits are fully optimized and validated for the sample types listed on the product specific webpage and datasheet, as this can vary between kits. Each kit is supplied ready to use with one pre-coated 96-well plate, a detection antibody directly conjugated to HRP, and all other necessary reagents. These kits are ideal for researchers who want the convenience of a ready to use and optimized ELISA product. Some of these kits are also available prepackaged in larger 6 and 50 plate sizes.Our DuoSet Kits, in contrast, are ELISA development kits containing the capture and detection antibody, the mass-value calibrated standard, and streptavidin-HRP to prepare approximately 5 or 15 plates. Ancillary reagents will need to be used/purchased, and for most kits, we will recommend one of our Ancillary Reagent Kits, which contain the reagents we use ourselves in-house. DuoSet kits are validated only for cell culture supernatant samples and therefore require further development and validation for accurate measurement in more complex samples such as serum and plasma. Our DuoSet Kits offer an economical, flexible alternative for the experienced ELISA user.