CD9 Antibody, Biotin conjugated
Description
Definition and Role of CD9
CD9 (cluster of differentiation 9) is a transmembrane glycoprotein with four hydrophobic domains, belonging to the tetraspanin family. It plays roles in:
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Cell adhesion and motility: Interacts with integrins (e.g., αIIb/β3 in platelets) to regulate aggregation .
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Tumor suppression: Overexpression inhibits metastasis in solid tumors .
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Neurological processes: Supports Schwann cell migration and neuronal differentiation .
The biotin-conjugated antibody facilitates detection via streptavidin-based assays, enhancing sensitivity in techniques like flow cytometry and Western blotting .
Key Clones
Reactivity
All clones exhibit specificity for human CD9, with no reported cross-reactivity to other tetraspanins .
Flow Cytometry
Western Blot
Immunohistochemistry
Research Findings
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- Studies have shown that CD9 is highly expressed in highly metastatic hepatocellular carcinoma (HCC) cells and promotes HCC cell migration. This suggests that CD9 may be a potential target for regulating the invasive behavior of HCC cells. PMID: 29749468
- The species-specific distribution of CD9 and CD81 during sperm maturation was compared between mice and humans. Interestingly, CD9 and CD81 occupy distinct areas in mouse spermatozoa, whereas they are found together in the acrosomal cap of human spermatozoa. PMID: 29671763
- CD9 expression is a predictor of certain clinical characteristics and indicates a poor prognosis in acute lymphoblastic leukemia patients. PMID: 29286918
- Blocking CD9-CD81 interaction reduces exosome-mediated HIV-1 entry. PMID: 29429034
- Exosomal markers CD63 and CD9 are found at elevated levels in pancreatic tumor tissues. PMID: 28609367
- CD9 expression can be a biomarker for poor prognosis in invasive breast carcinoma. PMID: 28178752
- CD9 stabilizes gp130 by preventing its ubiquitin-dependent lysosomal degradation, thus promoting the IL6-gp130-bone marrow X-linked non-receptor tyrosine kinase-STAT3 signaling pathway, which maintains GSC self-renewal and tumorigenic capacity. PMID: 27740621
- CD9 is highly expressed on extravillous trophoblast (EVT) at the boundary region of EVT invasion and intravascular EVT. CD9 expression on Swan71 cells decreases under hypoxic conditions but increases upon co-culture with HUVEC. This suggests that CD9 may regulate human placentation by influencing EVT invasion under the influence of oxygen environment and maternal endothelial cells. PMID: 27780531
- CD34(-) HSCs are characterized by low expression of the tetraspanin CD9, which promotes homing, and high expression of the peptidase CD26, which inhibits homing. PMID: 28687990
- Research suggests that the ligand-binding site of integrin alphaVbeta3 binds to the constant region (helices A and B) of the EC2 domain of CD9, CD81, and CD151 antigens, contrary to previous models. PMID: 27993971
- CD9 should be further investigated as a potential target for glioblastoma treatment. PMID: 26573230
- Using tetraspanin CD9 in tandem with E-cadherin as a biomarker in renal cell carcinoma could help differentiate between types and predict the metastatic potential of RCC. PMID: 26855131
- CD9 is implicated in BCC invasiveness and metastases through cellular mechanisms involving specific CD9+ plasma membrane protrusions of BCCs. PMID: 25762645
- CD9-enriched microdomains negatively regulate LPS-induced receptor formation by preventing CD14 from accumulating into lipid rafts. [Review] PMID: 26378766
- Downregulation of CD9 promotes pancreatic cancer cell proliferation and migration, at least partially, by enhancing cell surface expression of EGFR. PMID: 25955689
- CD9 expression is upregulated and its expression correlates with tumor stage and lymph node metastasis in esophageal squamous cell carcinoma patients. PMID: 26045817
- While the precise role of CD9 remains unclear, it is not excluded from playing a vital role in the fertilization process. [review] PMID: 25536312
- CD9 participates in the dysmegakaryopoiesis that occurs in primary myelofibrosis. PMID: 25840601
- High CD9 levels are associated with B acute lymphoblastic leukemia. PMID: 26320102
- CD9-induced suppression of cell proliferation may involve the inhibition of phosphorylation of EGFR and the activity of PI3K/Akt and MAPK/Erk signaling pathways. PMID: 25760022
- OY-TES-1 downregulation in liver cancer cells inhibits cell proliferation by upregulating CD9 and downregulating NANOG. PMID: 25673160
- Low levels of CD9 were observed in conjunction with a novel nonsense mutation in glycoprotein Ibbeta in a patient with Bernard-Soulier syndrome. PMID: 26275786
- The cysteine residues involved in disulfide bridge formation in CD9 EC2 are essential for inhibiting multinucleated giant cell formation, but a conserved glycine residue in the tetraspanin-defining 'CCG' motif is not. PMID: 25551757
- Alterations in CD9 expression significantly disrupt cellular actin arrangement and endogenous cell contraction by interfering with RhoA signaling. PMID: 25184334
- The mechanism responsible for the negative regulation exerted by CD9 on LFA-1 adhesion does not involve changes in the affinity state of this integrin but seems to be related to alterations in its aggregation state. PMID: 26003300
- Hypoxia regulates CD9 expression and CD9-mediated keratinocyte migration through the p38/MAPK pathway. PMID: 25200404
- Breast cancer cells contain a nuclear CD9 pool, and abrogation of CD9 expression results in multipolar mitoses and polynucleation. PMID: 25103498
- Sialylation is involved in the development of multidrug resistance in AML cells, possibly through ST3GAL5 or ST8SIA4 regulating the activity of PI3K/Akt signaling and the expression of P-gp and MRP1. PMID: 24531716
- The switch from alphavbeta5 to alphavbeta6 integrin plays a key role in CD9-regulated cell migration and MMP-9 activation in keratinocytes. PMID: 25265322
- High expression of CD9 is statistically associated with older patients. PMID: 24553302
- Tetraspanins CD9 and CD63 block HIV-1-induced cell-cell fusion at the transition from hemifusion to pore opening. PMID: 24608085
- Loss of CD9 expression is associated with enhanced invasive potential of malignant mesothelioma. PMID: 24466195
- CD9 and CD151 support integrin-mediated signaling at the immunological synapse. PMID: 24723389
- Introduction of CD9 expression in Raji cells resulted in significantly increased cell proliferation and HDAC activity compared to mock transfected Raji cells. PMID: 24747564
- Heparin-binding epidermal growth factor and CD9 are likely involved in processes highly relevant for MS lesion formation. PMID: 24038577
- This study points to EGFR as a key mediator between CD9-mediated pro-MMP-9 release and cellular invasion of HT1080 cells. PMID: 24246676
- The second extracellular loop of CD9 was responsible for the upregulation of MMP-9 production. PMID: 23840773
- This is the first study to examine the expression and prognostic potential of tetraspanins in oral dysplasia. PMID: 24201754
- Low CD9 expression is associated with malignant mesothelioma. PMID: 23128478
- Both CD9/CD81-silenced cells and CD151-silenced cells showed delayed alpha3beta1-dependent cell spreading on laminin-332. PMID: 23613949
- CD9 acts as a scaffold and assembles a ternary JAM-A-CD9-alphavbeta3 integrin complex, from which JAM-A is released upon bFGF stimulation. PMID: 23389628
- These data suggest that CD9 is a novel marker for a human germinal center-B cell subset committed to the plasma cell lineage. PMID: 23291167
- CD9 overexpression was confirmed in osteotropic cells. CD9 was significantly overexpressed in bone metastases versus primary tumors and visceral metastatic lesions. PMID: 23225418
- Tetraspanin CD9 modulates the molecular organization of integrins in lymphatic endothelial cells, supporting various functions required for lymphangiogenesis. PMID: 23223239
- Low CD9 expression is associated with gallbladder neoplasms. PMID: 22613496
- This research identifies human male germ cells with the capability of long-term survival and cell turnover in the xenogeneic testis environment. PMID: 22592495
- Knockdown of CD9 by siRNA and blockage of CD9 activity by ALB6 in ovarian cancer cells demonstrate that constitutive activation of NF-kappaB is CD9-dependent and that CD9 is involved in anti-apoptosis. PMID: 22095071
- CD9 increases GCM1 expression via the cAMP/PKA signaling pathway, resulting in increased ERVWE1 expression. PMID: 19692500
- The absence or down-regulation of CD9 expression and point mutation may play a significant role in the pathway of malignant transformation in the BEAS-2B cells induced by mineral powder. PMID: 17997888
- CD9 associates with ADAM17 and, through this interaction, negatively regulates the sheddase activity of ADAM17. PMID: 21365281
Q&A
What are the primary applications of CD9 Antibody, Biotin conjugated in research?
CD9 Antibody conjugated to biotin is widely used in immunological assays such as flow cytometry (FACS), Western blotting (WB), immunohistochemistry (IHC), immunocytochemistry (ICC), and enzyme-linked immunosorbent assays (ELISA). These applications leverage the antibody's ability to bind specifically to the CD9 molecule, a member of the tetraspanin family involved in cell adhesion, motility, and signaling pathways . The biotin conjugation enhances detection sensitivity by enabling interactions with streptavidin-based systems, which are commonly used for signal amplification in these assays .
How does CD9's role as a tetraspanin protein influence experimental outcomes?
CD9 is a transmembrane protein that interacts with integrins and other membrane proteins to regulate processes such as cell adhesion, migration, and fusion. Its presence on exosome membranes makes it a critical marker for extracellular vesicle studies . Researchers need to account for its broad tissue distribution and functional diversity when designing experiments to avoid misinterpretation of results due to off-target effects or overlapping functions with other tetraspanins like CD63 and CD81 .
What species specificity should be considered when using CD9 Antibody, Biotin conjugated?
Most commercially available CD9 antibodies are reactive with human samples but may also show cross-reactivity with mouse, rat, or other species due to conserved epitopes within the tetraspanin family . Researchers should verify the antibody's specificity through validation experiments such as Western blotting or IHC using positive and negative controls from the intended species .
How can researchers optimize signal-to-noise ratios when using biotin-conjugated antibodies for flow cytometry?
To achieve optimal signal-to-noise ratios in flow cytometry experiments using biotin-conjugated antibodies, researchers should perform a biotin blocking step after binding the antibody to streptavidin-coated beads or surfaces. This step prevents nonspecific binding of endogenous biotin-containing molecules, which can interfere with assay specificity . Additionally, careful titration of antibody concentrations and validation using isotype controls are recommended .
What are the critical considerations for studying extracellular vesicles (EVs) using CD9 antibodies?
CD9 is a prominent marker for EVs due to its abundant expression on exosome membranes. Researchers studying EVs must ensure that their isolation protocols preserve the integrity of exosomes while minimizing contamination from other cellular components. Validation of antibody specificity for EV-bound CD9 versus cell-surface CD9 is crucial . Additionally, researchers should note that expression levels of CD9 vary depending on the cell type of origin, which may influence experimental outcomes .
How can researchers address contradictory data regarding CD9's role in cell fusion processes?
CD9 has been implicated both as an inhibitor and facilitator of cell fusion in different contexts—e.g., inhibiting myotube fusion during muscle regeneration while enhancing sperm-egg fusion during fertilization . To resolve contradictions in data, researchers should design experiments that account for tissue-specific expression patterns and interactions with co-factors like integrins or other tetraspanins (e.g., CD81). Comparative studies across different cell types or developmental stages may also provide clarity .
How can researchers validate the specificity of biotin-conjugated CD9 antibodies in Western blotting?
Validation involves running Western blot assays with known positive control samples (e.g., human colon cancer tissue lysates) and negative controls where CD9 expression is absent or knocked down via siRNA techniques. Researchers should confirm that observed bands correspond to the expected molecular weight (~25 kDa) under reducing conditions . Using secondary antibodies conjugated to HRP or fluorescent dyes can enhance detection sensitivity .
What are best practices for antigen retrieval in IHC experiments involving CD9?
Antigen retrieval methods vary depending on tissue type and fixation conditions. For human colon cancer tissue sections stained with biotin-conjugated CD9 antibodies, heat-mediated retrieval using EDTA buffer (pH 8.0) or citrate buffer (pH 6.0) has been shown to improve epitope accessibility without damaging tissue morphology . It is recommended that researchers optimize retrieval protocols based on empirical testing across different samples .
How can researchers quantify biotin molecules per antibody structure?
Although manufacturers do not routinely measure the number of biotin molecules per antibody structure, estimates range from 3–6 molecules per antibody depending on conjugation conditions . Researchers requiring precise quantification can use mass spectrometry or HPLC-based methods to determine biotinylation levels experimentally .
How should researchers interpret discrepancies in band sizes during Western blot analysis of CD9?
Observed discrepancies in band sizes (~23–27 kDa versus expected ~25 kDa) may arise due to post-translational modifications like glycosylation or alternative splicing variants of CD9 . Researchers should perform deglycosylation assays or use peptide mapping techniques to confirm the identity of detected bands . Including molecular weight markers and loading controls ensures accurate interpretation of results.
What statistical methods are recommended for analyzing flow cytometry data involving CD9?
Flow cytometry data analysis requires robust statistical methods such as gating strategies based on fluorescence intensity thresholds and multivariate analysis for comparing populations stained with biotin-conjugated antibodies versus isotype controls . Software tools like FlowJo or FCS Express can facilitate data visualization and quantitative comparisons across experimental groups .
What storage conditions are ideal for preserving biotin-conjugated antibodies?
Biotin-conjugated antibodies should be stored at -20°C in buffers containing cryoprotectants like glycerol or trehalose to prevent freeze-thaw degradation . Avoid exposure to light as it may degrade biotin molecules over time . Aliquoting into smaller volumes minimizes repeated freeze-thaw cycles during experimental use.
How can researchers address nonspecific staining observed during IHC experiments with CD9 antibodies?
Nonspecific staining may result from inadequate blocking steps or high antibody concentrations. Researchers should optimize blocking conditions using serum from the host species of secondary antibodies (e.g., goat serum for anti-rabbit secondary antibodies) . Serial dilutions of primary antibodies can help identify optimal working concentrations while minimizing background signals.
