MA1001L-T3 Humanized anti-human CD3 monoclonal antibody (OKT3)

Background

CD3 is a dimeric complex composed of CD3γ, δ, ε, η, and ζ subunits, which non-covalently associates with the T cell receptor (TCR) to jointly execute essential functions in T cell biology. CD3 is responsible for transducing antigen recognition signals from the extracellular environment to the T cell cytoplasm, thereby regulating T cell activation and TCR cell surface expression. Mutations in CD3 are closely associated with various immune system disorders, such as severe combined immunodeficiency (SCID). CD3 is broadly expressed on the surface of approximately 95% of mature T cells and NKT cells, and is also expressed to varying degrees on developing thymocytes. Additionally, most T cell tumors express CD3. The OKT3 antibody specifically recognizes and binds to an extracellular conformational epitope on the CD3ε subunit (approximately 20 kDa) within the TCR/CD3 complex. This epitope is exposed when CD3ε associates with CD3γ or CD3δ, and OKT3 binding to this epitope induces T cell activation. Due to its immunosuppressive properties in vivo, the OKT3 antibody has been demonstrated to be effective in treating allograft transplant rejection. Furthermore, clone OKT3 is widely used for human T cell phenotyping and has been observed to block the binding of anti-CD3 antibody clones SK7 and UCHT1. This product is a humanized recombinant monoclonal antibody expressed and produced in CHO cells, using serum-free, animal-free, chemically defined medium, and purified by alkali-tolerant Protein A chromatography, ensuring high purity and safety. The storage buffer is PBS, free of carrier proteins or other additives. The production process is strictly controlled for adventitious agents, significantly enhancing the safety, stability, and reliability of the product, makng it suitable for cell culture and a wide range of scientific research applications.

Product Specification

Directions for Use

This product is in liquid form at a concentration of 1 mg/mL in 1× PBS (pH 7.4).

Thaw at 2–8°C or room temperature before use and mix gently. For T cell activation, it is typically used in combination with CD28 antibody (MA1002L). Optimization of antibody working concentration based on the specific culture system and cytokine combination is recommended.

In CAR-T manufacturing, CD3 + CD28 antibodies can be coated onto culture plate/magnetic bead surfaces or added directly to the culture medium. The coating concentration and method should be optimized and validated according to the specific process. Aliquot for single-use storage to avoid repeated freeze-thaw cycles.

Transport & Storage

Dry ice transport.

Store at -20°C or below, protected from light and sealed. After opening, aliquot into single-use portions to avoid repeated freeze-thaw cycles.

Applications

Humanized anti-human CD3 monoclonal antibody (OKT3) specifically targets the extracellular conformational epitope of the CD3ε subunit within the TCR/CD3 complex. CD3 is a member of the immunoglobulin superfamily and plays a central role in antigen recognition, signal transduction, and T cell activation — transmitting MHC-antigen peptide information from the TCR to the intracellular compartment.

Widely used in:

• T cell activation and expansion in CAR-T cell manufacturing

• TIL (tumor-infiltrating lymphocyte) manufacturing

• T cell proliferation from peripheral blood / bone marrow / cord blood mononuclear cells

• T cell phenotyping (classic tool antibody)

• T cell activation and signal transduction research

• Graft-versus-host disease (GvHD) and transplant immunology research

• Immunotherapy process development

OKT3 is one of the most classic CD3 antibodies in T cell research. It recognizes a different CD3ε epitope from UCHT1 (MA1001L-T1) and can block SK7 and UCHT1 binding. It is recommended for use in combination with CD28 antibody (MA1002L) to meet T cell activation requirements across different cell sources and process conditions.

Quality Control

Expression host: CHO cells, chemically defined serum-free medium 

Purity: > 95% (dual validation by SDS-PAGE + SEC-HPLC) 

Concentration: 1 mg/mL, buffer system 1× PBS (pH 7.4) 

Safety: serum-free, animal-free, free of adventitious agent contamination

Precautions

• This product is intended for research, process development, and biomanufacturing use only. Not for diagnostic, therapeutic, or clinical use in humans or animals.

• Use the product as soon as possible after opening. Unused portions should be promptly sealed and stored under recommended conditions.

• Maintain aseptic technique throughout handling to avoid microbial contamination.

• Aliquot for single-use storage to avoid repeated freeze-thaw cycles that may compromise antibody activity.

• Optimal antibody concentration may vary across different cell types and experimental systems. Determine optimal usage conditions through preliminary experiments.

• Read the product technical datasheet carefully before use and follow relevant experimental protocols.