{"product_id":"cd21-antibody-bha17115143","title":"CD21 Antibody","description":"\u003ch2\u003eOverview\u003c\/h2\u003e \u003cp\u003eCD21 Antibody is a research-use primary antibody intended for detection of \u003cstrong\u003eCD21\u003c\/strong\u003e in experimental workflows. It is supplied in \u003cstrong\u003ePurified\u003c\/strong\u003e format. Key antibody attributes include Mouse, Monoclonal (mouse origin), clone CR2\/2754, isotype Mouse IgG1, kappa. Applications listed for this product include ELISA, FACS, WB, IF, IHC-P. Reported\/annotated localization context: Cell surface. Species reactivity (as provided): Human.\u003c\/p\u003e \u003ch2\u003eKey elements and design rationale\u003c\/h2\u003e \u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eTarget:\u003c\/strong\u003e CD21 — selectivity and interpretation should be considered in the context of isoforms, post-translational modifications, and related family members when applicable.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFormat:\u003c\/strong\u003e Purified — format can influence background, multiplexing compatibility, and downstream detection strategies.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAntibody identity:\u003c\/strong\u003e Mouse, Monoclonal (mouse origin), clone CR2\/2754, isotype Mouse IgG1, kappa — these attributes help align secondary reagents and controls (e.g., isotype-matched controls) with your assay design.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eLocalization:\u003c\/strong\u003e Cell surface — expected subcellular distribution can guide band\/structure interpretation and help flag off-target signal.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct notes (from provided description):\u003c\/strong\u003e Recognizes a protein of 140kDa, which is identified as the complement receptor 2 (CR2)\/CD21. Its epitope is located in 5-8 short consensus repeats (SCRs). This mAb is highly specific to CR2 and shows no cross-reaction with CR1. This protein is expressed strongly on mature B cells, follicular dendritic cells and weakly on immature thymocytes and T lymphocytes. In B-cell ontogeny, CD21 appears after the pre-B-stage, is maintained during peripheral B-cell development and is lost upon terminal differentiation into plasma cells. CD21 expression is also gradually lost after stimulation of B cells in vitro. CD21 functions as receptor for C3d, C3dg and iC3b Complement components, for EBV and for IFNalpha. CD21 binds to CD23 and associates with CD19, CD81 and Leu13 to form a large signal-transduction complex involved in B cell activation.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eWhere multiple assay formats are possible, align the antibody format, host\/isotype, and listed applications with your detection system and controls to support clear interpretation of signal.\u003c\/p\u003e \u003ch2\u003eBiological background\u003c\/h2\u003e \u003cp\u003eIn this catalog, CD21 is positioned within \u003cstrong\u003eImmunology \u0026amp; Inflammation, Infectious Disease\u003c\/strong\u003e research contexts. Localization annotations (e.g., Cell surface) can help contextualize expected signal patterns in imaging and fractionation-based readouts. For authoritative gene\/protein nomenclature, domains\/isoforms, and curated functional annotations, consult resources such as UniProt, NCBI Gene, and Ensembl.\u003c\/p\u003e \u003ch2\u003eResearch relevance and current trends\u003c\/h2\u003e \u003cul\u003e\n\u003cli\u003eHigher-plex and spatially resolved readouts (e.g., multiplex IF\/IHC, spatial omics) are increasing demand for well-characterized primary antibodies with clearly stated host\/isotype and labeling strategies.\u003c\/li\u003e\n\u003cli\u003eGenetic perturbation controls (knockout\/knockdown) and orthogonal measurements (e.g., RNA vs protein) are commonly used to strengthen target attribution when interpreting antibody-derived signals.\u003c\/li\u003e\n\u003cli\u003eReproducibility initiatives emphasize transparent reporting of antibody identity (clone, host, isotype) and experimental context to improve cross-study comparability.\u003c\/li\u003e\n\u003c\/ul\u003e \u003ch2\u003eCommon research applications\u003c\/h2\u003e \u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eELISA:\u003c\/strong\u003e interpret changes in signal in the context of sample composition, epitope accessibility, and potential isoform\/PTM differences across conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFACS:\u003c\/strong\u003e interpret changes in signal in the context of sample composition, epitope accessibility, and potential isoform\/PTM differences across conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWB:\u003c\/strong\u003e interpret changes in signal in the context of sample composition, epitope accessibility, and potential isoform\/PTM differences across conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIF:\u003c\/strong\u003e interpret changes in signal in the context of sample composition, epitope accessibility, and potential isoform\/PTM differences across conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eIHC-P:\u003c\/strong\u003e interpret changes in signal in the context of sample composition, epitope accessibility, and potential isoform\/PTM differences across conditions.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTypical workflow themes:\u003c\/strong\u003e Western blot validation, IHC on FFPE tissue, IF\/ICC localization, Flow cytometry staining, ELISA binding assay, Specificity controls.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWorkflow notes:\u003c\/strong\u003e Validate CD21 by Western blot in cell\/tissue lysates (include controls), Detect CD21 by IHC in FFPE tissue sections (optimize antigen retrieval + dilution), Detect CD21 localization by IF\/ICC in cultured cells (optimi…\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eWhen comparing conditions, consistent sample processing and appropriate negative\/positive controls support interpretation of qualitative localization differences and quantitative abundance changes.\u003c\/p\u003e \u003ch2\u003eNotes for experimental interpretation\u003c\/h2\u003e \u003cul\u003e\n\u003cli\u003eIsoforms and post-translational modifications may shift apparent molecular weight or epitope accessibility, especially across cell states or treatments.\u003c\/li\u003e\n\u003cli\u003eSpecies and tissue context can affect sequence conservation, expression level, and background binding; predicted reactivity should be verified in your sample.\u003c\/li\u003e\n\u003cli\u003eControl concepts include isotype-matched controls, secondary-only controls (for indirect detection), and genetic\/orthogonal controls (e.g., KO\/KD, independent antibodies, or RNA measurements) when feasible.\u003c\/li\u003e\n\u003c\/ul\u003e \u003cp\u003eMonoclonal and polyclonal antibodies can differ in epitope recognition breadth and lot-to-lot characteristics; consider clonality and clone information (when provided) alongside your assay requirements. Conjugated formats may simplify detection but can change background and multiplexing behavior compared with unconjugated primaries.\u003c\/p\u003e \u003c!-- Sources (internal): - UniProt Knowledgebase (UniProtKB) — UniProt Consortium — https:\/\/www.uniprot.org\/ - NCBI Gene — National Center for Biotechnology Information (NCBI) — https:\/\/www.ncbi.nlm.nih.gov\/gene\/ - Ensembl Genome Browser — EMBL-EBI — https:\/\/www.ensembl.org\/ - The Human Protein Atlas — Human Protein Atlas — https:\/\/www.proteinatlas.org\/ - Antibody validation concepts and controls (general guidance) — NIH \/ community resources — https:\/\/www.nih.gov\/ - MIQE\/experimental reporting \u0026 reproducibility (general) — Scientific community guidelines — https:\/\/www.equator-network.org\/ --\u003e","brand":"NSJ Bioreagents","offers":[{"title":"0.2 mg\/ml in 1X PBS with 0.1 mg\/ml BSA (US sourced) and 0.05% sodium azide \/ 100 ug","offer_id":53044933951853,"sku":"V3971-100UG","price":559.0,"currency_code":"USD","in_stock":true},{"title":"0.2 mg\/ml in 1X PBS with 0.1 mg\/ml BSA (US sourced) and 0.05% sodium azide \/ 20 ug","offer_id":53045076230509,"sku":"V3971-20UG","price":259.0,"currency_code":"USD","in_stock":true},{"title":"Prediluted in 1X PBS, 0.1 mg\/ml BSA (US sourced), 0.05% sodium azide; *For IHC use only* \/ 7 ml","offer_id":53045076263277,"sku":"V3971IHC-7ML","price":559.0,"currency_code":"USD","in_stock":true},{"title":"1 mg\/ml in 1X PBS; BSA free, sodium azide free \/ 100 ug","offer_id":53045076296045,"sku":"V3971SAF-100UG","price":559.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0949\/7424\/7277\/files\/get_image_bd2f6ab8-e9dc-4f16-bd57-8809f7833345.jpg?v=1782236896","url":"https:\/\/www.ebiohippo.com\/products\/cd21-antibody-bha17115143","provider":"BioHippo","version":"1.0","type":"link"}