CD28 and CTLA-4, together with their ligands, B7-1 and B7-2, constitute one of the dominant costimulatory pathways that regulate T and B cell responses. CD28 and CTLA-4 are structurally homologous molecules that are members of the immunoglobulin (Ig) gene superfamily. Both CD28 and CTLA-4 are composed of a single Ig
V‑like extracellular domain, a transmembrane domain and an intracellular domain. CD28 and CTLA-4 are both expressed on the cell surface as disulfide-linked homodimers or as monomers. The genes encoding these two molecules are closely linked on human chromosome 2 and mouse chromosome 1. Mouse CD28 is expressed constitutively on virtually 100% of mouse T cells and on developing thymocytes. Cell surface expression of mouse CD28 is down-regulated upon ligation of CD28 in the presence of PMA or PHA. In contrast, CTLA-4 is not expressed constitutively but is up-regulated rapidly following T cell activation and CD28 ligation. Cell surface expression of mouse CTLA-4 peaks approximately 48 hours after activation. Although both CTLA-4 and CD28 can bind to the same ligands, CTLA-4 binds to B7-1 and B7-2 with a 20-100 fold higher affinity than CD28. CD28/B7 interaction has been shown to prevent apoptosis of activated T cells via the upregulation of Bcl-xL. CD28 ligation has also been shown to regulate Th1/Th2 differentiation.
Human CD28 Antibody
R&D Systems | Catalog # MAB342R
Recombinant Monoclonal Antibody.
Key Product Details
Species Reactivity
Human
Applications
Western Blot, Agonist Activity
Label
Unconjugated
Antibody Source
Recombinant Monoclonal Mouse IgG1 Clone # 37407R
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Product Specifications
Immunogen
S. frugiperda insect ovarian cell line Sf 21-derived recombinant human CD28
Asn19-Pro152
Accession # P10747
Asn19-Pro152
Accession # P10747
Specificity
Detects human CD28 in direct ELISAs.
Clonality
Monoclonal
Host
Mouse
Isotype
IgG1
Endotoxin Level
<0.10 EU per 1 μg of the antibody by the LAL method.
Applications for Human CD28 Antibody
Application
Recommended Usage
Agonist Activity
0.2-0.6 µg/mL
Sample: Jurkat human acute T cell leukemia cell line
Sample: Jurkat human acute T cell leukemia cell line
Western Blot
1 µg/mL
Sample: Recombinant Human CD28 Fc Chimera (Catalog # 342-CD) under non-reducing conditions only
Sample: Recombinant Human CD28 Fc Chimera (Catalog # 342-CD) under non-reducing conditions only
Reviewed Applications
Read 1 review rated 5 using MAB342R in the following applications:
Formulation, Preparation, and Storage
Purification
Protein A or G purified from cell culture supernatant
Reconstitution
Reconstitute at 0.5 mg/mL in sterile PBS. For liquid material, refer to CoA for concentration.
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Formulation
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose. *Small pack size (SP) is supplied either lyophilized or as a 0.2 µm filtered solution in PBS.
Shipping
Lyophilized product is shipped at ambient temperature. Liquid small pack size (-SP) is shipped with polar packs. Upon receipt, store 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, 2 to 8 °C under sterile conditions after reconstitution.
- 6 months, -20 to -70 °C under sterile conditions after reconstitution.
Calculators
Background: CD28
References
- Lenschow, D.J. et al. (1996) Annu. Rev. Immunol. 14:233.
- Hathcock, K.S. and R.J. Hodes (1996) Advances in Immunol. 62:131.
- Ward, S.G. (1996) Biochem. J. 318:361.
Alternate Names
CD28
Gene Symbol
CD28
UniProt
Additional CD28 Products
Product Documents for Human CD28 Antibody
Certificate of Analysis
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Note: Certificate of Analysis not available for kit components.
Product Specific Notices for Human CD28 Antibody
For research use only
Customer Reviews for Human CD28 Antibody (1)
5 out of 5
1 Customer Rating
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Application: Functional AssaySample Tested: Peripheral blood T cellsSpecies: HumanVerified Customer | Posted 02/16/201996-well plates were coated with anti-CD3e -/+ AF-342R and incubated with isolated CD8+ T-cells from human PBMCs. Activation was read through intracellular interferon.
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Protocols
Find general support by application which include: protocols, troubleshooting, illustrated assays, videos and webinars.
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- R&D Systems Quality Control Western Blot Protocol
- Troubleshooting Guide: Western Blot Figures
- Western Blot Conditions
- Western Blot Protocol
- Western Blot Protocol for Cell Lysates
- Western Blot Troubleshooting
- Western Blot Troubleshooting Guide
- View all Protocols, Troubleshooting, Illustrated assays and Webinars