Anti-Human CD20 (Rituximab) [Clone 10F381] – PE

Anti-Human CD20 (Rituximab) [Clone 10F381] – PE

Product No.: LT904

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Product No.LT904
Clone
10F381
Target
CD20
Product Type
Biosimilar Recombinant Human Monoclonal Antibody
Alternate Names
B1; S7; Bp35; CVID5; MS4A2; LEU-16; MS4A1; membrane spanning 4-domains A1
Isotype
Human IgG1κ
Applications
FC

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Antibody Details

Product Details

Reactive Species
Cynomolgus Monkey
Rhesus Monkey
Human
Host Species
Human
Expression Host
HEK-293 Cells
FC Effector Activity
Active
Immunogen
Human lymphoblastoid cell line SB.
Product Concentration
0.2 mg/ml
Formulation
This R-phycoerythrin (R-PE) conjugate is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.4, 1% BSA and 0.09% sodium azide as a preservative.
Storage and Handling
This R-phycoerythrin (R-PE) conjugate is stable when stored at 2-8°C. Do not freeze.
Regulatory Status
Research Use Only (RUO). Non-Therapeutic.
Country of Origin
USA
Shipping
Next Day 2-8°C
Excitation Laser
Blue Laser (488 nm) and/or Green Laser (532 nm)/Yellow-Green Laser (561 nm)
Applications and Recommended Usage?
Quality Tested by Leinco
FC The suggested concentration for Rituximab biosimilar antibody for staining cells in flow cytometry is ≤ 1.0 μg per 106 cells in a volume of 100 μl. Titration of the reagent is recommended for optimal performance for each application.
Each investigator should determine their own optimal working dilution for specific applications. See directions on lot specific datasheets, as information may periodically change.

Description

Description

Specificity
This non-therapeutic biosimilar antibody uses the same variable region sequence as the therapeutic antibody Rituximab. Clone 10F381 recognizes human CD20. This product is for research use only.
Background
CD20 is a 33-37 kD transmembrane-spanning phosphoprotein found on the surface of developing B-cells and various B-cell malignancies. CD20 is a popular target for mAb therapy because depleting developing B-cells generally does not cause permanent side effects (due to the fact that mature plasma cells and B-cell progenitors do not express CD20 and that there is limited expression of CD20 among other cell lineages). Rituximab is a chimeric monoclonal antibody that binds to CD20. The precise function of CD20 is still unknown. However, it is suspected to play a role in Ca2+ influx across plasma membranes, maintaining intracellular Ca2+ concentration, and allowing the activation of B cells. Rituximab is used to treat some autoimmune diseases and types of cancer such as non-Hodgkin lymphoma, chronic lymphocytic leukemia, and rheumatoid arthritis among others. The Fc portion of Rituximab mediates antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Rituximab increases MHC II and adhesion molecules LFA-1 and LFA-3 (lymphocyte function-associated antigen) and also induces apoptosis of CD20+ cells. This ultimately results in the elimination of B cells (including the cancerous ones) from the body, and thus allows a new population of healthy B cells to develop from lymphoid stem cells. Anti-Human CD20 (Rituximab) utilizes the same variable regions from the therapeutic antibody Rituximab making it ideal for research projects.
Antigen Distribution
CD20 is primarily found on the surface of immune system B cells. CD20 is highly expressed in the lymph node, and to a lesser extent, the spleen and appendix.
PubMed
NCBI Gene Bank ID
Research Area
Biosimilars
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Costimulatory Molecules
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Immunology

Leinco Antibody Advisor

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Research-grade Rituximab biosimilars are commonly used as calibration standards or reference controls in pharmacokinetic (PK) bridging ELISAs to ensure accurate quantification of Rituximab concentrations in serum samples, facilitating dose-response assessments and PK profiling. These biosimilars serve as stand-ins for the reference commercially available Rituximab (Rituxan®/MabThera®), especially when the reference product is scarce, expensive, or when strictly controlled research standards are required.

Key points regarding their use:

  • Calibration Standards:
    Research-grade Rituximab biosimilars are used to create a standard curve by preparing serial dilutions that span the assay’s detection range (e.g., 0.1–1000 ng/mL), with a known concentration acting as the reference for quantification. The resulting calibration curve is then applied to convert the optical density (OD) signals from unknown serum samples into Rituximab concentration values.

  • Reference Controls:
    Biosimilars as reference controls allow validation of assay performance, including accuracy, linearity, and reproducibility across runs. The standards provided are sometimes explicitly calibrated against both the originator Rituximab (such as Rituxan™) and alternate biosimilar products, and in some kits, they are also referenced to international standards (e.g., from the National Institute of Biologicals and Control, NIBSC).

  • Bridging ELISA Principle:
    PK bridging ELISA typically uses:

    • An anti-idiotypic antibody as capture reagent (specific to Rituximab idiotype).
    • Serum samples or standards with Rituximab/biosimilar are added; bound by the immobilized anti-idiotype antibody.
    • A detection antibody (often anti-human IgG, HRP-conjugated) binds to Fc region of captured Rituximab.
    • Signal intensity correlates to drug concentration; quantification is based on the biosimilar-calibrated standard curve.
  • Validation and Equivalence:
    For PK measurements to be valid, the biosimilar standard must be shown to have analytical equivalency to the reference product in the assay system, ensuring that both originator and biosimilar drugs are detected with the same efficiency.

  • Documentation and Traceability:
    Kits and protocols specify that calibration and equivalence are lot-specific and traceable to known units (e.g., International Units from NIBSC), which is critical for reproducibility and regulatory compliance in PK studies.

In summary:
Research-use Rituximab biosimilars are fit-for-purpose reagents for generating calibration curves (standards) or serving as reference controls in PK ELISAs, enabling precise and accurate measurement of Rituximab drug levels in serum—a crucial step for pharmacokinetic analyses.

Biopharma companies employ a comprehensive array of analytical assays to confirm the structural and functional similarity of a proposed biosimilar to the originator (reference) biologic. These assays span both structural and functional characterization, forming the foundation for biosimilar approval decisions.

Typical Analytical Assays Used:

Structural Characterization:

  • Primary structure analysis: Confirming the amino acid sequence, often via mass spectrometry or peptide mapping, to ensure identical sequence to the originator.
  • Higher-order structure: Examined using techniques such as circular dichroism and nuclear magnetic resonance (NMR) to assess secondary and tertiary structural similarity.
  • Posttranslational modifications: Analysis of glycosylation patterns, oxidation, deamidation, and other chemical modifications by mass spectrometry and chromatography.
  • Aggregation/fragmentation and purity/impurity profiles: Typically examined using size-exclusion chromatography, capillary electrophoresis, and related orthogonal methods.
  • Product-related variants: Including aggregates, precursors, and truncated forms are characterized to assess comparability.

Functional Characterization:

  • Binding assays: Test the biosimilar’s binding affinity to the nominal target and to key receptors (e.g., FcγR for antibodies), often using surface plasmon resonance or ELISA.
  • Cell-based bioassays: Assess the mechanism of action—for instance, cell proliferation, cytotoxicity, or other relevant biological outcomes.
  • Enzyme kinetics and potency assays: Evaluate whether functional activity matches the reference product.
  • Immunogenicity assays (preclinical): Predict potential immune reactions.
  • Companies use multiple orthogonal assays—different methods targeting the same attribute to increase confidence in results.

These analyses are performed as head-to-head comparisons against the reference product, often across multiple lots to account for natural variability and establish statistical similarity.

Role of Leinco Biosimilars in These Studies:

  • Leinco Technologies produces research-grade biosimilars that are used as analytical reference standards in biosimilar development workflows. Their products can be used in the structure-function studies described above to serve as a well-characterized comparator during early and development-phase biosimilar characterization, assay development, and sometimes as controls for lot-to-lot variability studies.
  • It is important to note that regulatory agencies typically require that analytical similarity be demonstrated using the FDA- or EMA-approved reference product, not a research-grade biosimilar like those from Leinco, for product licensure. However, Leinco’s biosimilars can be invaluable for:
    • Assay development and validation prior to engaging in official regulatory comparability studies.
    • Analytical method optimization, as a control or surrogate where the originator is not available or for initial process development.

Key Points:

  • The entire biosimilar comparability exercise is focused on critical quality attributes (CQAs)—specific structural and functional features known to impact clinical safety and efficacy.
  • When minor structural differences are detected, robust functional assays are critical to demonstrate these are not clinically meaningful.

If you need assay-specific protocols or further detail on methodologies applied to a particular class of biosimilar (such as mAb or cytokine biosimilars), please specify.

References & Citations

1. Mato, A. et al. (2018) Oncologist. 23(3):288-296.
2. Richards, K. et al. (2018) Front Oncol. 8: 163.
Flow Cytometry

Certificate of Analysis

Formats Available

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Disclaimer AlertProducts are for research use only. Not for use in diagnostic or therapeutic procedures.