CD28 and CTLA-4, together with their ligands, B7-1 and B7-2, constitute one of the dominant co-stimulatory 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 up-regulation of bcl-XL. CD28 ligation has also been shown to regulate Th1/Th2 differentiation.
Post-translational: Phosphorylated by LCK (PubMed:7568038). Dephosphorylated by PTPN11 (PubMed:36114179). Tyrosine phosphorylated induced by CD40LG.
生物活性
Immobilized Recombinant Human CD28 Protein (rp301926) at 1.0 μg/mL can bind Theralizumab (anti-CD28) (Ab190136) with the EC50 of 311.2 ng/mL.
36.3-46.5 kDa, under reducing conditions; 60.5-74.8 kDa, under non-reducing conditions.
分子类型
蛋白质
产品线
生物产品
储存与运输
物理形态
冻干(Lyophilized)
储存缓冲液
Lyophilized from PBS, pH 7.4
浓度
见COA
复溶
We recommend that this vial be briefly centrifuged prior to opening to bring the contents to the bottom. Reconstitute at 1.0 mg/mL in sterile distilled water. Stock solutions should be apportioned into working aliquots and stored at ≤ -20 °C. Further dilutions should be made in appropriate buffered solutions.
储存条件
-20°C储存,避免反复冻融
运输条件
超低温运输
稳定性与储存
-20℃保存 12个月;复溶后建议分装,避免反复冻融。
图片
Recombinant Human CD28 Protein (rp301926) - ELISA
Immobilized Recombinant Human CD28 Protein (rp301926) at 1.0 μg/mL can bind Theralizumab (anti-CD28) (Ab190136) with the EC₅₀ of 311.2 ng/mL.
Recombinant Human CD28 Protein (rp301926) - SDS-PAGE
3 μg/lane of Recombinant Human CD28 Protein was resolved with SDS-PAGE under reducing (R) and non-reducing (N) conditions and visualized by Coomassie® Blue staining, showing a band at 36.3-46.5 kDa under reducing conditions and 60.5-74.8 kDa under non-reducing conditions.
CD28 can form homodimers through disulfide bonds (PMID: 35397202).