Biolegend, 122021, Ultra-LEAF™ Purified anti-mouse CD28 Antibody, 100μg

CD28 is a 44 kD glycoprotein, also known as Tp44 or T44. It is a member of the Ig superfamily, expressed on thymocytes, most peripheral T cells, and NK cells. In association with CD80 (B7-1) and CD86 (B7-2), CD28 acts as the second signal for T and NK cell activation and proliferation. The E18 antibody blocks the binding of 37.51 antibody to CD28 and costimulates T cell activation and proliferation.
100μg
Verified Reactivity: Mouse
Antibody Type: Monoclonal
Host Species: Mouse
Immunogen: A20 cells and recombinant mCD28Ig
Formulation: 0.2 µm filtered in phosphate-buffered solution, pH 7.2, containing no preservative.
Endotoxin Level: Less than 0.01 EU/µg of the protein (< 0.001 ng/µg of the protein) as determined by the LAL test.
Preparation: The Ultra-LEAF™ (Low Endotoxin, Azide-Free) antibody was purified by affinity chromatography.
Concentration: The antibody is bottled at the concentration indicated on the vial, typically between 2 mg/mL and 3 mg/mL. Older lots may have also been bottled at 1 mg/mL. To obtain lot-specific concentration and expiration, please enter the lot number in our Certificate of Analysis online tool.
Storage & Handling: The antibody solution should be stored undiluted between 2°C and 8°C. This Ultra-LEAF™ solution contains no preservative; handle under aseptic conditions.
Application: FC - Quality testedCostim, Block - Reported in the literature, not verified in house
Recommended Usage: Each lot of this antibody is quality control tested by immunofluorescent staining with flow cytometric analysis. For flow cytometric staining, the suggested use of this reagent is ≤ 1.0 µg per million cells in 100 µl volume. It is recommended that the reagent be titrated for optimal performance for each application.
Application Notes: Additional reported applications (for the relevant formats) include: in vitro costimulation of T and NK cells1, in vitro blocking of allogeneic mixed leukocyte response and inhibition of MHC-unrestricted CTL cytotoxicity, and in vitro induction of thymocyte differentiation. The LEAF™ purified antibody (Endotoxin <0.1 EU/µg, Azide-Free, 0.2 µm filtered) is recommended for functional assays (Cat. No. 122004).
Application References(PubMed link indicates BioLegend citation): Dennehy KM, et al. 2006. J. Immunol. 176:5725.
Product Citations: Duraiswamy J, et al. 2021. Cancer Cell. 39:1623. PubMed Fajstova A, et al. 2020. Cells. 9:00. PubMed
RRID: AB_2810370 (BioLegend Cat. No. 122021) AB_2810371 (BioLegend Cat. No. 122022)
Structure: Ig superfamily, 44 kD
Distribution: Thymocytes, CD4+, CD8+ peripheral T cells, NK cells
Function: Costimulates T and NK cells
Ligand/Receptor: CD80 (B7-1), CD86 (B7-2)
Cell Type: NK cells, T cells, Thymocytes, Tregs
Biology Area: Costimulatory Molecules, Immunology
Molecular Family: CD Molecules
Antigen References: 1. Barclay AN, et al. 1997. The Leukocyte Antigen FactsBook Academic Press. 2. Lenschow DJ, et al. 1996. Annu. Rev. Immunol. 14:233. 3. Gross JA, et al. 1992. J. Immunol. 149:380.
Gene ID: 12487
UniProt: View information about CD28 on UniProt.org
Clone: E18
Regulatory Status: RUO
Other Names: Tp44, T44
Isotype: Mouse IgG2b, κ
Q: Do you guarantee that your antibodies are totally pathogen free?
A: BioLegend does not test for pathogens in-house aside from the GoInVivo™ product line. However, upon request, this can be tested on a custom basis with an outside, independent laboratory.
Q: Does BioLegend test each Ultra-LEAF™ antibody by functional assay?
A: No, BioLegend does not test Ultra-LEAF™ antibodies by functional assays unless otherwise indicated. Due to the possible complexities and variations of uses of biofunctional antibodies in different assays and because of the large product portfolio, BioLegend does not currently perform functional assays as a routine QC for the antibodies. However, we do provide references in which the antibodies were used for functional assays and we do perform QC to verify the specificity and quality of the antibody based on our strict specification criteria.
Q: Does BioLegend test each Ultra-LEAF™ antibody for potential pathogens?
A: No, BioLegend does not test for pathogens in-house unless otherwise indicated.  However, we can recommend an outside vendor to perform this testing as needed.
Q: Have you tested this Ultra-LEAF™ antibody for in vivo or in vitro applications?
A: We don't test our antibodies for in vivo or in vitro applications unless otherwise indicated. Depending on the product, the TDS may describe literature supporting usage of a particular product for bioassay. It may be best to further consult the literature to find clone specific information.