PE Anti-Human CR2/CD21 Monoclonal Antibody for FC - P20023

Core Product Specifications and Parameters

Biological Background: Complement Receptor Type 2 (CR2/CD21) Function and Localization

• Complement receptor type 2 (CR2, also known as CD21) is a membrane glycoprotein encoded by the CR2 gene. Alternative splicing results in multiple isoforms with observed molecular weights ranging from approximately 110 kDa to 119 kDa, and the polypeptide backbone has a calculated mass of ~113 kDa. It belongs to the sushi/SCR domain-containing receptor family.
• CR2 serves as a high-affinity receptor for complement component C3d. When C3d is bound to antigens, CR2 on B cells facilitates antigen recognition and uptake, enhancing B-cell activation and downstream immune responses. This interaction plays a central role in linking innate and adaptive immunity. Related references: PMID:1849076 PMID:21527715 PMID:7753047
• CR2 forms the B-cell coreceptor complex together with CD19, CD81, and FCRL5 on the surface of B lymphocytes. This multiprotein assembly is critical for amplifying B-cell receptor (BCR) signals and modulating B-cell activation. Related references: PMID:1383329 PMID:30107486
• Independent of the CD19-BCR complex, CR2 can trigger specific intracellular signaling by activating the tyrosine kinase SRC, which phosphorylates nucleolin/NCL and leads to activation of AKT and GSK3 kinases in a SYK/CD19-independent manner. Related references: PMID:12938232
• CR2 also acts as a ligand for CD23 (FcεRII), the low-affinity IgE receptor, and thus participates in the regulation of IgE production. This interaction provides a link between the complement system and allergic responses. Related references: PMID:1386409
• In addition to its immunological roles, CR2 serves as an entry receptor for Epstein-Barr virus (EBV) on B cells and epithelial cells, contributing to the virus's tropism and pathogenesis.
• CR2 is expressed primarily on mature B lymphocytes, follicular dendritic cells, and to a lesser extent on T lymphocytes, pharyngeal epithelial cells, and astrocytes. This restricted expression pattern reflects its specialized functions in immune tissues.
• Post-translational modifications include N-linked glycosylation and disulfide bond formation, which are essential for the structural integrity of its extracellular sushi domains. The protein contains a single transmembrane helix and a short cytoplasmic tail.

Experimental Guidance and Technical Tips

• The immunogen comprises the entire extracellular domain (amino acids 21–971) of human CD21, making this PE-conjugated antibody suitable for detecting native cell surface CR2 on live, unfixed cells by flow cytometry.
• For flow cytometry, consider titrating the antibody to determine the optimal concentration for your specific cell system. Human peripheral blood B lymphocytes or CR2-expressing cell lines (e.g., Raji) can serve as positive controls.
• Protect the antibody from light to maintain PE fluorophore stability, and avoid multiple freeze-thaw cycles to preserve conjugate integrity.
• Because CR2 is also expressed on follicular dendritic cells and some T-cell subsets, confirm cell-type specificity using appropriate gating strategies and co-staining markers.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio provides diagnostic manufacturers and research laboratories with a comprehensive range of IVD raw materials, from validated antibody pairs to rare target reagents. This PE anti-CR2/CD21 monoclonal antibody supports immunology, infectious disease, and coreceptor research applications. For bulk quantities, custom conjugation, or technical assistance, contact our sourcing team to streamline your procurement process.