CTLA 4 Human

Cytotoxic T-Lymphocyte Associated Antigen-4 Human Recombinant

Recombinant human CTLA-4, produced in E. coli, is a single polypeptide chain with a molecular weight of 15.9 kDa. It consists of 149 amino acids (residues 36-161). The protein includes a 23 amino acid His-tag fused at the N-terminus and is purified using proprietary chromatographic techniques.
Shipped with Ice Packs
Cat. No.
BT20253
Source
Escherichia Coli.
Appearance
The product is a colorless solution that has undergone sterile filtration.

CTLA4 Human, igG-His

Cytotoxic T-Lymphocyte Associated Antigen-4 Human Recombinant, igG-His Tag

Produced in Sf9 Baculovirus cells, CTLA4 is a single, glycosylated polypeptide chain with a molecular weight of 40.8kDa (368 amino acids, 36-161a.a.). However, on SDS-PAGE, the molecular size appears to be between 40-57kDa. This CTLA4 protein is expressed with a 239 amino acid hIgG-His-tag at the C-Terminus and purified using proprietary chromatographic techniques.
Shipped with Ice Packs
Cat. No.
BT20411
Source
Sf9, Baculovirus cells.
Appearance
A sterile, colorless solution.

CTLA4 Human, IgG-His, Active

CTLA4 Human Recombinant, igG-His Tag, Active

Recombinant human CTLA4, expressed in Sf9 insect cells using a baculovirus expression system, is a single, glycosylated polypeptide chain. This protein consists of 368 amino acids (residues 36-161), resulting in a molecular weight of 40.8 kDa. For purification and detection purposes, a 242 amino acid hIgG-His tag is fused to the C-terminus of CTLA4.

Shipped with Ice Packs
Cat. No.
BT20489
Source
Sf9, Baculovirus cells.
Appearance
A clear, colorless solution that has been sterilized by filtration.

CTLA4 Human, Sf9

Cytotoxic T-Lymphocyte Associated Antigen-4 Human Recombinant, Sf9

Recombinant CTLA4 protein, expressed in Sf9 insect cells using a baculovirus system, is a single, glycosylated polypeptide chain. It encompasses 135 amino acids (residues 36-161) and possesses a molecular weight of 14.6 kDa. On SDS-PAGE, the protein's apparent molecular size ranges from approximately 18 to 28 kDa. This CTLA4 variant features a 6-amino acid His tag at its C-terminus, facilitating purification via proprietary chromatographic methods.
Shipped with Ice Packs
Cat. No.
BT20596
Source
Sf9, Baculovirus cells.
Appearance
The product appears as a clear, colorless liquid that has been sterilized by filtration.

CTLA4 Mouse

Cytotoxic T-Lymphocyte Associated Antigen-4 Mouse Recombinant

Recombinant Mouse CTLA4, produced in Sf9 insect cells, is a single, glycosylated polypeptide chain. It consists of 363 amino acids (specifically, amino acids 38 to 161) and has a molecular mass of 40.6 kDa. On SDS-PAGE, its apparent molecular size ranges from 40 kDa to 57 kDa. This CTLA4 protein is engineered with a 239 amino acid hIgG-His-tag at the C-terminus and is purified using proprietary chromatographic techniques.
Shipped with Ice Packs
Cat. No.
BT20679
Source
Sf9 Insect cells.
Appearance
A clear, colorless solution that has been sterilized by filtration.
Definition and Classification

Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), also known as CD152, is a protein receptor that functions as an immune checkpoint and downregulates immune responses . It belongs to the immunoglobulin superfamily and is homologous to the T-cell co-stimulatory protein, CD28 .

Biological Properties

Key Biological Properties: CTLA-4 is a type I transmembrane protein consisting of 223 amino acids . It has a single Ig-V (variable)-like domain on its extracellular portion .

Expression Patterns: CTLA-4 is constitutively expressed in regulatory T cells (Tregs) and is upregulated in conventional T cells upon activation . It is also expressed in various other immune cells and some non-immune cells .

Tissue Distribution: CTLA-4 is predominantly found in lymphoid tissues such as the lymph nodes, spleen, and thymus . It is also expressed in other tissues including the pancreas and testis .

Biological Functions

Primary Biological Functions: CTLA-4 plays a crucial role in maintaining immune homeostasis by acting as an inhibitory receptor on T cells . It downregulates T cell activation and proliferation, thereby preventing excessive immune responses .

Role in Immune Responses: CTLA-4 is essential in regulating the amplitude of T cell responses. It competes with CD28 for binding to B7 molecules (CD80 and CD86) on antigen-presenting cells (APCs), thereby inhibiting T cell activation .

Pathogen Recognition: While CTLA-4 itself is not directly involved in pathogen recognition, its regulatory role ensures that immune responses to pathogens are kept in check to prevent autoimmunity .

Modes of Action

Mechanisms with Other Molecules and Cells: CTLA-4 primarily functions by outcompeting CD28 for binding to B7 molecules on APCs . This competitive inhibition prevents the co-stimulatory signal required for full T cell activation .

Binding Partners: The primary binding partners of CTLA-4 are CD80 (B7-1) and CD86 (B7-2) on APCs .

Downstream Signaling Cascades: Upon binding to its ligands, CTLA-4 transmits inhibitory signals that reduce the production of interleukin-2 (IL-2) and inhibit cell cycle progression in T cells .

Regulatory Mechanisms

Expression and Activity Control: The expression and activity of CTLA-4 are tightly regulated by various mechanisms including ligand-induced expression, cell surface translocation, rapid internalization, recycling, and degradation .

Transcriptional Regulation: CTLA-4 expression is regulated at the transcriptional level by various transcription factors that respond to immune signals .

Post-Translational Modifications: CTLA-4 undergoes several post-translational modifications that affect its stability, localization, and function .

Applications

Biomedical Research: CTLA-4 is extensively studied in the context of immune regulation and autoimmunity .

Diagnostic Tools: CTLA-4 expression levels can serve as biomarkers for certain autoimmune diseases and cancers .

Therapeutic Strategies: CTLA-4 inhibitors, such as monoclonal antibodies, are used in cancer immunotherapy to enhance anti-tumor immune responses . Conversely, CTLA-4 agonists are explored for treating autoimmune diseases by dampening excessive immune activity .

Role in the Life Cycle

Development: CTLA-4 is crucial for the development and function of regulatory T cells, which are essential for maintaining immune tolerance from early development .

Aging: The regulatory role of CTLA-4 continues throughout life, helping to prevent age-related autoimmunity .

Disease: Dysregulation of CTLA-4 is associated with various diseases, including autoimmune disorders and cancers . Its role in these conditions makes it a critical target for therapeutic interventions .

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