Anti-Human CD28 (IB20) Antibody (ICH5023A-0.1mg)

Please refer to the specific buffer information in the hardcopy of datasheet or the lot-specific COA.

Anti-Human CD28 (clone IB20) is a recombinant human IgG4 monoclonal antibody directed against human CD28, supplied as a research-use-only reagent well suited to functional immunology and T-cell biology studies. The human IgG4 backbone is a common choice for work modelling therapeutic-format antibodies because IgG4 engages Fc-gamma receptors and complement only weakly, limiting Fc-mediated effector activity and helping isolate the contribution of receptor engagement itself. This makes the clone appropriate for T-cell costimulation and activation assays, receptor-blocking or -ligation experiments, and characterisation of CD28-dependent signalling. It is produced to a low-endotoxin specification suitable for sensitive primary-cell and functional work, where endotoxin contamination would otherwise confound activation readouts, and is available in bulk milligram-to-gram quantities for larger screening campaigns, assay development, and reproducible lot use across a project. As a research-grade reagent it is intended for in-vitro and ex-vivo experimental use and is not a clinical product. Reactivity is against the human antigen, so rodent in-vivo depletion or blockade regimens developed for mouse-reactive clones do not apply directly. CD28 is the principal costimulatory receptor on T cells and provides "signal 2" alongside T-cell receptor engagement (signal 1). It is a disulphide-linked homodimeric glycoprotein of the immunoglobulin superfamily, constitutively expressed on most CD4+ and a subset of CD8+ T cells. CD28 binds the B7 ligands CD80 (B7-1) and CD86 (B7-2) on antigen-presenting cells. Ligation lowers the threshold for T-cell activation, promotes IL-2 production, drives clonal expansion and survival through upregulation of anti-apoptotic proteins, and supports metabolic reprogramming of activated T cells. Signalling proceeds via PI3K and other adaptors recruited to the cytoplasmic tail. CD28 costimulation is counter-regulated by CTLA-4, which shares the same B7 ligands but delivers inhibitory signals, making the CD28/CTLA-4/B7 axis central to the balance between T-cell activation and tolerance.