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Human CD81 antigen(CD81) ELISA kit

Product#: CS-CSB-EL004960HU-IS
$834.80
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DCP-PIC100X

Protease Inhibitor Cocktail (100X)

Included with every order
 DCP-SM1AbTBS1X

SigMax 1Ab-TBS

Included with every order
 DCP-UTBS1X

Universal Blocking Buffer

Included with every order
 DCP-SM2AbTBS1X

SigMax 2Ab-TBS

Included with every order

+ the 5th component, matched to your kit's detection method:

DCP-HRPTBS1X

HRPQuench-TBS

Exclusively for HRP-based kits
OR
DCP-ALPTBS1X

ALPQuench-TBS

Exclusively for ALP-based kits

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Human ELISA Kit · Immunology

Human CD81 antigen(CD81) ELISA kit

Sandwich quantitative immunoassay for Human CD81 antigen(CD81) ELISA kit in human serum, plasma, cell lysates, tissue homogenates  available in multiple catalog sizes:

Trial 24T 96T

Note: Please send inquiries regarding Trial 24T orders to support@diagnocine.com.

Detection Range
23.5-1,500 pg/mL
Sensitivity
11.75 pg/mL
Assay Time
1-5 hours
Sample Volume
50-100 μL
Product specifications
Uniprot No.P60033
SpeciesHomo sapiens (Human)
Sample typesserum, plasma, cell lysates, tissue homogenates
Detection range23.5 pg/mL-1500 pg/mL
Sensitivity11.75 pg/mL
Assay time1-5h
Sample loading volume50-100μL
Detection wavelength450 nm
Assay principleSandwich (Quantitative)
Data analysisStandard curve + Curve Expert software
Research areaImmunology
Storage condition2-8°C (see protocol for full details)
Shipping condition4 °C
Shelf life6 months
Human CD81 antigen(CD81) ELISA kit serum plasma cell lysates tissue homogenates Immunology Human ELISA
Lead Time

10 business days

Processing + 3-5 days shipping

Availability

In Stock : USA

Worldwide shipping available

Assay principle
Sample prep
Antibody capture
450 nm detection
Standard curve
Quantification

In this sandwich ELISA, Human CD81 antigen(CD81) ELISA kit in the sample is captured between a pre-coated capture antibody and a detection antibody. Signal intensity is proportional to analyte concentration. Quantification uses a standard curve fitted with Curve Expert software, covering 23.5 pg/mL-1500 pg/mL with a minimum detectable dose of 11.75 pg/mL.

For research use only (RUO). Not intended for diagnostic or therapeutic purposes. Validated in human serum, plasma, cell lysates, tissue homogenates matrices only.
Description

This ELISA kit provides quantitative measurement of CD81 (TAPA-1) in human serum, plasma, cell lysates, and tissue homogenates, supporting immunological research into this tetraspanin's roles in immune cell signaling and viral entry. Because CD81 is predominantly membrane-bound and shed at low levels into circulation, accurate quantification demands both high sensitivity and compatibility across soluble and cell-associated sample formats.

Detection Range: The 23.5–1500 pg/mL range accommodates the low picogram-level concentrations of soluble CD81 typically found in human plasma while also capturing elevated levels observed in hepatic inflammation and chronic HCV infection, minimizing the need for extensive sample concentration or dilution.

Alternative Names
26 kDa cell surface protein TAPA 1 ELISA Kit; 26 kDa cell surface protein TAPA-1 ELISA Kit; 26 kDa cell surface protein TAPA1 ELISA Kit; CD 81 ELISA Kit; CD81 ELISA Kit; CD81 antigen (target of antiproliferative ELISA Kit 1) ELISA Kit; CD81 antigen ELISA Kit; CD81 molecule ELISA Kit; CD81_HUMAN ELISA Kit; CVID6 ELISA Kit; S5.7 ELISA Kit; TAPA 1 ELISA Kit; TAPA1 ELISA Kit; Target of the antiproliferative ELISA Kit 1 ELISA Kit; Tetraspanin 28 ELISA Kit; Tetraspanin-28 ELISA Kit; Tetraspanin28 ELISA Kit; Tspan 28 ELISA Kit; Tspan-28 ELISA Kit; Tspan28 ELISA Kit
Function
Structural component of specialized membrane microdomains known as tetraspanin-enriched microdomains (TERMs), which act as platforms for receptor clustering and signaling. Essential for trafficking and compartmentalization of CD19 receptor on the surface of activated B cells. Upon initial encounter with microbial pathogens, enables the assembly of CD19-CR2/CD21 and B cell receptor (BCR) complexes at signaling TERMs, lowering the threshold dose of antigen required to trigger B cell clonal expansion and antibody production. In T cells, facilitates the localization of CD247/CD3 zeta at antigen-induced synapses with B cells, providing for costimulation and polarization toward T helper type 2 phenotype. Present in MHC class II compartments, may also play a role in antigen presentation. Can act both as positive and negative regulator of homotypic or heterotypic cell-cell fusion processes. Positively regulates sperm-egg fusion and may be involved in acrosome reaction. In myoblasts, associates with CD9 and PTGFRN and inhibits myotube fusion during muscle regeneration. In macrophages, associates with CD9 and beta-1 and beta-2 integrins, and prevents macrophage fusion into multinucleated giant cells specialized in ingesting complement-opsonized large particles. Also prevents the fusion of mononuclear cell progenitors into osteoclasts in charge of bone resorption. May regulate the compartmentalization of enzymatic activities. In T cells, defines the subcellular localization of dNTPase SAMHD1 and permits its degradation by the proteasome, thereby controlling intracellular dNTP levels. Also involved in cell adhesion and motility. Positively regulates integrin-mediated adhesion of macrophages, particularly relevant for the inflammatory response in the lung.; (Microbial infection) Acts as a receptor for hepatitis C virus (HCV) in hepatocytes. Association with CLDN1 and the CLDN1-CD81 receptor complex is essential for HCV entry into host cell.; (Microbial infection) Involved in SAMHD1-dependent restriction of HIV-1 replication. May support early replication of both R5- and X4-tropic HIV-1 viruses in T cells, likely via proteasome-dependent degradation of SAMHD1.; (Microbial infection) Specifically required for Plasmodium falciparum infectivity of hepatocytes, controlling sporozoite entry into hepatocytes via the parasitophorous vacuole and subsequent parasite differentiation to exoerythrocytic forms.
Gene References into Functions
  1. These data revealed the crucial role played by His490 and His621 in hepatitis C virus infection, particularly during CD81 binding in cell entry. PMID: 25701820
  2. IFI6 inhibits HCV entry by impairing EGFR mediated CD81/CLDN1 interactions. This may be relevant to other virus entry processes employing EGFR. PMID: 25757571
  3. findings suggest that homozygous CD81 rs708564 TT may be a genetic modifier for avoiding HCV infection whether as a sole single nucleotide polymorphism or combined with the CLDN1 rs893051 GG genotype PMID: 25934191
  4. Data suggest that the intramolecular 188-196 bond restricts the intrinsic conformational dynamics of D-helix of cluster of differentiation 81 (CD81)-large extracellular loop (LEL), which is essential for hepatitis C virus entry. PMID: 26116703
  5. LDLR was not required for the degradation of CD81 by PCSK9, but its presence strengthened the PCSK9 effect. PMID: 26195630
  6. Results suggest that the CD81 antigen (CD81) expressed by B cells has differential effects on B cell proliferation or apoptosis according to Epstein-Barr virus (EBV) infection and the expression level of CD81. PMID: 26498453
  7. CD81 expression was lower in systemic sclerosis patients compared to controls independent of disease duration. PMID: 26926492
  8. Study used molecular dynamics simulations to gain insights into the role of local conformational flexibility in nanodomain formation in the plasma membrane, using the tetraspanin molecule CD81 as a model; suggest that exposing a flexible domain of CD81 enables binding to interaction partners by circumventing the restriction of orientation and conformational freedom of membrane proteins PMID: 27276264
  9. CD81 cell surface expression had a negative impact on survival in acute myeloid leukemia. PMID: 27566555
  10. The transmembrane segments of CD81 pack as two largely separated pairs of helices, capped by the large extracellular loop (EC2) at the outer membrane leaflet. The two pairs of helices converge at the inner leaflet to create an intramembrane pocket with additional electron density corresponding to a bound cholesterol molecule within the cavity. PMID: 27881302
  11. Results from crystallography and molecular dynamics of CD81 long-extracellular loop (LEL) show that its flexibility is an inherent molecular property likely to be tuned by variation in pH and redox conditions. This tuning mechanism would explain the priming role ascribed to CD81LEL in rendering the virus-receptor complex fusogenic during cell entry. PMID: 27916518
  12. A new link between HCV receptor molecules and the hepatocyte glycocalyx, namely, CD81 and Synd-1. PMID: 27930836
  13. CD81 is preferentially expressed in first trimester human placentas and progressively down-regulated with gestation advance in normal physiological conditions. CD81 up-regulation is detected in trophoblasts and cells in the villous core, and maternal sera of patients with early-onset severe preeclampsia. PMID: 28167787
  14. Studies have shown that CD81 regulates cell migration and invasion, and has therefore been implicated in tumor growth, cancer progression and metastasis. CD81 is expressed in most types of cancer, and the overexpression or down-regulation of this molecule has been correlated with either good or bad prognosis. [review] PMID: 28408492
  15. Free energy calculations indicated that the E2/CD81 binding process might follow a two-step model involving (i) the electrostatic interaction-driven initial binding of human-specific E2-site2, followed by (ii) changes in the E2 orientation to facilitate the hydrophobic and van der Waals interaction-driven binding of E2-site1 PMID: 28481946
  16. results demonstrate that the interaction of CD81 with SAMHD1 controls the metabolic rate of HIV-1 replication by tuning the availability of building blocks for reverse transcription, namely dNTPs.Together with its role in HIV-1 entry and budding into host cells, the data indicate that HIV-1 uses CD81 as a rheostat that controls different stages of the infection PMID: 28871089
  17. Tetraspanin hCD81 backbone domains are critical to signal for productive Hepatitis C Virus entry. A cholesterol-coordinating glutamate residue in CD81 promotes HCV infection. The backbone domains of hCD81 are additional HCV susceptibility-determining factors. PMID: 29677132
  18. CD81 might be a potential prognostic biomarker associated with poor patient prognosis in breast cancer. PMID: 30117494
++ 32 more research findings link this target to additional biology. Showing the 18 most recent — the full set appears on the complete datasheet.
Involvement in disease
Immunodeficiency, common variable, 6 (CVID6)
Tissue Specificity
Expressed on B cells (at protein level). Expressed in hepatocytes (at protein level). Expressed in monocytes/macrophages (at protein level). Expressed on both naive and memory CD4-positive T cells (at protein level).
Subcellular Location
Cell membrane; Multi-pass membrane protein. Basolateral cell membrane; Multi-pass membrane protein.
Protein Families
Tetraspanin (TM4SF) family
Database Links

HGNC: 1701

OMIM: 186845

KEGG: hsa:975

STRING: 9606.ENSP00000263645

UniGene: Hs.54457

Precision

Intra-assay Precision (Precision within an assay): CV%<8%

Three samples of known concentration were tested twenty times on one plate to assess.

Inter-assay Precision (Precision between assays): CV%<10%

Three samples of known concentration were tested in twenty assays to assess.

Typical Data

These standard curves are provided for demonstration only. A standard curve should be generated for each set of samples assayed.

Human CD81 antigen(CD81) ELISA kit

pg/ml

OD1

OD2

Average

Corrected

1500

2.425

2.534

2.480

2.319

750

1.535

1.617

1.576

1.416

375

0.923

0.938

0.930

0.770

187.5

0.489

0.509

0.499

0.339

94

0.332

0.321

0.326

0.166

47

0.250

0.253

0.251

0.091

23.5

0.212

0.204

0.208

0.047

0

0.163

0.158

0.160

Linearity

To assess the linearity of the assay, samples were spiked with high concentrations of Human CD81 in various matrices and diluted with the Sample Diluent to produce samples with values within the dynamic range of the assay.

Sample

Serum(n=4)

1:2

Average %

95

Range %

88-101

1:4

Average %

102

Range %

97-106

1:8

Average %

87

Range %

80-94

1:16

Average %

93

Range %

86-98

Recovery

The recovery of Human CD81 spiked to levels throughout the range of the assay in various matrices was evaluated. Samples were diluted prior to assay as directed in the Sample Preparation section.

Sample Type

Average % Recovery

Range

Serum (n=5)

91

85-96

EDTA plasma (n=4)

99

92-107

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