Anti-CD28 Antibody

The CD28 antigen is a disulfide-linked homodimeric costimulatory receptor of the immunoglobulin superfamily, expressed on most peripheral CD4+ and CD8+ T lymphocytes and weighing approximately 44 kDa per subunit. Engagement of CD28 by the B7 ligands CD80 and CD86 on antigen-presenting cells delivers the second signal required alongside TCR stimulation to drive IL-2 transcription, clonal expansion, and full T-cell activation, making it a central checkpoint in adaptive immunity research. This unconjugated rabbit polyclonal reagent from Antibodies.com was raised against the human CD28 protein and is validated for Western blot and ELISA applications on human samples. The conjugate-free format is supplied as 100 µl of stock antiserum in a vial, allowing end users to couple the antibody to biotin, HRP, fluorophores, or magnetic beads for downstream immunohistochemistry, immunoprecipitation, or flow cytometry workflows. For routine use, store working aliquots at -20 °C and protect from light to limit freeze-thaw degradation of the IgG fraction and preserve binding activity across multiple experiments.