0.2 µm filtered in phosphate-buffered solution, pH 7.2, containing no preservative. Endotoxin level is <0.1 EU/µg of the protein (<0.01 ng/µg of the protein) as determined by the LAL test.
The LEAF™ (Low Endotoxin, Azide-Free) antibody was purified by affinity chromatography.
Biolegend LEAF Purified Human CD28单抗302913
Storage & Handling:
The CD28 antibody solution should be stored undiluted between 2°C and 8°C. This LEAF™ solution contains no preservative; handle under aseptic conditions.
FC – Quality tested Costim, IP, IHC – Reported in the literature
Each lot of this antibody is quality control tested byimmunofluorescent 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 or 100 µl of whole blood. It is recommended that the reagent be titrated for optimal performance for each application.
Additional reported applications (for the relevant formats) include: immunoprecipitation, immunohistochemical staining of acetone-fixed frozen tissue sections4, and in vitro T cell costimulation5-8. This clone was tested in-house and does not work on formalin fixed paraffin-embedded (FFPE) tissue. The CD28.2 antibody co-stimulates T cell proliferation and cytokine production in the presence of suboptimal amounts of anti-CD3 antibody. The LEAF™ purified antibody (Endotoxin <0.1 EU/μg, Azide-Free, 0.2 μm filtered) is recommended for functional assays (Cat. No. 302914). For highly sensitive assays, we recommend Ultra-LEAF™ purified antibody (Cat. No. 302934) with a lower endotoxin limit than standard LEAF™ purified antibodies (Endotoxin <0.01 EU/µg).
1. Schlossman S, et al. Eds. 1995. Leucocyte Typing V. Oxford University Press. New York. 2. Nunes J, et al. 1993. Biochem. J. 293:835. 3. Calea-Lauri J, et al. 1999. J. Immunol. 163:62. 4. Tazi A, et al. 1999. J. Immunol. 163:3511. (IHC) 5. Marti F, et al. 2001. J. Immunol. 166:197. (Costim) 6. Jeong SH, et al. 2004. J. Virol. 78:6995. (Costim) 7. Rivollier A, et al. 2004. Blood 104:4029. (Costim) 8. Scharschmidt E, et al. 2004. Mol. Cell Biol. 24:3860. (Costim) 9. Sheng W, et al. 2007.Elsevier 580:6819. PubMed 10. Mitsuhashi M. 2007. Clin Chem.53:148. PubMed 11. Ye Z, et al. 2008. Infect. Immun. 76:2541. PubMed 12. Magatti M, et al. 2008. Stem Cells 26:182. (FA) PubMed
Human peripheral blood lymphocytes stained with LEAF™ purified CD28.2, followed by anti-mouse IgGs FITC
Human peripheral blood mononuclear cells were stained with CFSE on day 0, and then stimulated with (filled histogram) or without (open histogram) immobilized LEAF™ Purified CD3 (clone UCHT1) and LEAF™ purified CD28 (clone CD28.2) for 3 days. On day 4, cells were harvested and stained with CD4 Brilliant Violet 711™. Dot plot (above) was analyzed on live cells. Histogram data (below) was analyzed by gating on CD4 positive cells.
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CD28 is a 44 kD disulfide-linked homodimeric type I glycoprotein. It is a member of the immunoglobulin superfamily and is also known as T44 or Tp44. CD28 is expressed on most T lineage cells, NK cell subsets, and plasma cells. CD28 binds both CD80 and CD86 using a highly conserved motif MYPPY in the CDR3-like loop. CD28 is considered a major co-stimulatory molecule, inducing T lymphocyte activation and IL-2 synthesis, and preventing cell death. In vitro studies indicate that ligation of CD28 on T cells by CD80 and CD86 on antigen presenting cells provides a costimulatory signal required for T cell activation and proliferation.
Ig superfamily, type I transmembrane glycoprotein, homodimer, 44 kD
Mature T cells, thymocytes, NK cell subsets, plasma cells, EBV-positive B cells
T cell costimulation
1. Schlossman S, et al. Eds. 1995. Leucocyte Typing V. Oxford University Press. New York. 2. June CH, et al. 1994. Immunol. Today 15:321. 3. Linskey PS, et al. 1993. Annu. Rev. Immunol. 11:191.