Anti-Mouse CD40-BX045 (3/23); Alexa Fluor™ 647-RX045 (C906-25Tests)

CD40, also known as TNFSF5, is a type I transmembrane protein and member of the TNF receptor family. The binding of CD40L (CD154) on TH cells to CD40 activates antigen presenting cells and induces a variety of downstream effects1. CD40 is expressed on B cells, dendritic cells, monocytes, thymic epithelial cells and, at low levels, on T cells 2. Signaling though CD40 plays an important role in the proliferation and differentiation of B cells and is critical for immunoglobulin (Ig) class switching3. The membrane-anchored CD40L is expressed almost exclusively on activated CD4+ T lymphocytes. Failure to express CD40L leads to "immunodeficiency with hyper-IgM", a disease characterized by failure to produce IgG, IgA and IgE. Some of the early intracellular signaling by the CD4-CD40L system includes the association of the CD40 with TRAFs and the activation of various kinases 4. Adaptor protein TNFR2 interacts with this receptor and serves as a mediator of the signal transduction. The interaction of CD4-CD40L is found to be necessary for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis. PhenoCycler-Fusion (CODEX)® reporters are made up of a fluorescent dye and a short oligonucleotide DNA barcode called a PhenoCycler-Fusion (CODEX)® Tag. Fluorescent reporters enable highly specific detection of corresponding barcodes, and the use of spectrally separated dyes allow for precise signal detection in up to three distinct fluorescence channels at one time.