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    1. Human SARS-CoV-2 S1 RBD IgG Antibody ELISA Kit

      • 中文名称:
        人新型冠状病毒S糖蛋白RBD(SARS-CoV-2 S1 RBD) IgG抗体 ELISA Kit
      • 货号:
      • 规格:
      • 价格:
      • 其他:


      • 产品描述:

        The product CSB-EL33241HU is an easy-to-use ELISA Kit intended for the qualitative detection of SARS-CoV-2 S1 RBD IgG antibody in human serum and plasma in vitro. SARS-CoV-2 S1 RBD IgG is an indicator of a recent or prior COVID infection. Infected patients develop IgG against SARS-CoV-2 S1 RBD 7 days post-infection, and IgG content peaks in the third week (IgM was close to vanishing at this time). IgG lasts in the blood for months or even years. After secondary infection, IgG levels in the body of patients increase rapidly and substantially in the short term and remain in the body for a long time, while IgM rarely increases. Serological testing may help to diagnose suspected patients with negative RT–PCR (real-time polymerase chain reaction) results and identify asymptomatic infections.

        The measurement of this assay is based on the indirect ELISA principle, in which the immune complex pre-coated antigen/S1 RBD IgG antibody/HRP-conjugated IgG is formed and then develops color reaction after the addition of TMB substrate solution. The color intensity is directly proportional to the amount of SARS-CoV-2 S1 RBD IgG antibody bound at the initial step. This kit serves as a tool to provide performance data during SARS-CoV-2-related research and development. The OD (optical density) of the sample below 2.1x negative OD was considered negative, and equal or above 2.1x negative OD was positive. It has high throughput with 90 samples at a time (6 wells used for the control) and has been validated with excellent specificity and high precision (less than 15%).

      • 别名:
        Human SARS-CoV-2 (COVID-19, 2019-nCoV) S1 RBD IgG Antibody ELISA Kit; S glycoprotein RBD IgG Antibody ELISA Kit; Spike glycoprotein RBD IgG Antibody ELISA Kit
      • 缩写:
        SARS-CoV-2 S RBD Ab (IgG)
      • Uniprot No.:
      • 种属:
        Homo sapiens (Human)
      • 样本类型:
        serum, plasma
      • 检测范围:
      • 反应时间:
      • 样本体积:
      • 检测波长:
        450 nm
      • 研究领域:
        Infectious Diseases
      • 测定原理:
      • 测定方法:
      • 精密度:
        Intra-assay Precision (Precision within an assay): CV%<15%
        Three samples of known concentration were tested twenty times on one plate to assess.
        Inter-assay Precision (Precision between assays): CV%<15%
        Three samples of known concentration were tested in twenty assays to assess.
      • 标准曲线:
        Test parameter specification test result
        Positive control ≥1.0 1.256
        Negative control ≤0.25 0.193
        Positive rate 20,Positive 100%
        Negative rate 20,Negative 100%
      • 本试剂盒所含材料:
        • A 96-well Coated assay plate 1 -- This microplate has been pre-coated with human SARS-CoV-2 S1 RBD antigen.
        • Negative Control (1 x 800 μl) -- It is free of the SARS-CoV-2 S1 RBD IgG antibody and used to preclude the false positive.
        • Positive Control (1 x 800 μl) -- Used to evaluate the validity, stability, and comparability of the test results.
        • HRP-conjugated anti-Human IgG antibody (100 x concentrate) (1 x 120 μl) -- Act as the detection antibody.
        • HRP-conjugate Diluent (1 x 20 ml) -- Dilute the HRPconjugated anti-Human IgG antibody.
        • Sample Diluent (2 x 20 ml) -- Dilute the sample solution.
        • Wash Buffer (25 x concentrate) (1 x 20 ml) -- Wash the unbound regeat.
        • TMB Substrate (1 x 10 ml) -- React with HRP, eliciting a chromogenic color reaction.
        • Stop Solution (1 x 10 ml) -- Stop the color reaction. The solution turns from blue to yellow.
        • Four Adhesive Strips (For 96 wells) -- Seal the microplate when incubation.
        • An Instruction manual



      • 本试剂盒不含材料:
        • A microplate reader capable of measuring absorbance at 450 nm, with the correction wavelength set at 540 nm or 570 nm.
        • An incubator that can provide stable incubation conditions up to 37°C±5°C.
        • Centrifuge
        • Vortex
        • Squirt bottle, manifold dispenser, or automated microplate washer.
        • Absorbent paper for blotting the microtiter plate.
        • 50-300ul multi-channel micropipette
        • 100ml and 500ml graduated cylinders.
        • Deionized or distilled water.
        • Pipette tips
        • Timer
        • Test tubes for dilution.



      • 货期:
        3-5 working days



      What is the differences between the SARS-CoV-2 S protein and N protein?


      Spike glycoprotein (S) is a structural protein that protrudes from the lipid envelop to form a typical bulbous, crown-like halo surrounding the viral particle. The S protein of SARS-CoV-2 functions to recognize the receptor, attach to and fuse with the host cell membrane during viral infection. Proteolysis by TMPRSS2 and cathepsin B/L exerts a vital role in priming SARS-CoV-2 S for entry. The S protein consists of two subunits: S1 (bulbous head region) and S2 (stalk region). The receptor-binding domain (RBD) within the S1 subunit is responsible for the recognition and binding to the host receptor ACE2. The S2 subunit is composed of fusion peptide (FP), heptapeptide repeat sequence 1 (HR1), HR2, transmembrane (TM) domain, and cytoplasmic domain fusion (CT), and is involved in the virus-cell fusion and viral entry. As the main antigen component of the SARS-CoV-2, S protein-targeted neutralizing antibodies (nAbs) can induce protective immunity against viral infection.

      Nucleocapsid (N) phosphoprotein, a structural protein of SARS-CoV-2, binds to the viral RNA, a process known as RNA encapsidation, forming the nucleocapsid. The N protein of SARS-CoV-2 comprises an N-terminal domain (NTD) that captures the viral RNA genome and a C-terminal domain (CTD) that anchors the ribonucleoprotein complex to the membrane by interacting with the viral membrane (M) protein during viral assembly. As a multifunctional molecule, the N protein not only participates in the process of RNA synthesis and folding but also affects host cellular responses to viral infection, including cell cycle and translation. It also contributes to viral transcription efficiency and pathogenesis.


      What is the assay procedure?


      1. Prepare all reagents and samples as instructed.
      2. Refer to the Assay Layout Sheet to calculate the number of the wells (including a blank well) to be used and put the remaining wells and the desiccant back into the pouch to seal and store at 4 °C.
      3. Add 100 µl positive control, negative control, or sample (may require dilution) to each well. Seal and incubate 30 minutes at  37°C.
      4. After thorough washing, add 100 μl HRP-conjugated Anti-Human IgG Antibody into each well (not to the blank well). Seal and incubate 30 minutes at  37 °C.
      5. Wash the unbound reagent and add 90 µl TMB Substrate Solution to each well. Incubate for 20 minutes at 37°C.
      6. Add 50 µl Stop Solution to each well and gently tap the plate to ensure thorough mixing. Take the blank well as zero and read the at 450 nm within 10 minutes using a microplate reader.


      What is the difference between IgG and IgM?


      Immunoglobulin G (IgG): It is the most common and abundant antibody in the body, accounting for about 70-80% of the total human immunoglobulins. IgG is generated in most patients within 7-10 days after symptoms develop and peaks in the third week and then declines to a lesser content level. It can be rapidly and substantially reproduced after a second exposure to the same antigen. A positive IgG test result indicates that the patient is in convalescence or prior infection. IgG test can be used for the course monitoring and retrospective diagnosis of patients (eg. COVID-19). IgG is largely responsible for long-term immunity after infection or vaccination. Unique among the immunoglobulins, IgG can pass through the placenta. IgG antibodies from the mother protect the fetus during the pregnancy and to the baby during its first few months of life. IgG is subdivided into four subclasses: IgG1, IgG2, IgG3, and IgG4.

      Immunoglobulin M (IgM): It is the first antibody produced in response to new infection or a new "non-self" antigen, providing short-term protection. IgM increases for several weeks and peaks in the second week and then declines as IgG synthesis begins. The positive blood test of IgM can be an indicator of early infection. Serological tests for IgM therefore can be used for the early screening of suspected cases.