MA1002L Humanized anti Human CD28 mAb

Background

CD28 monoclonal antibody specifically binds to CD28. CD28, also known as Tp44 or T44, is a 44 kD glycoprotein expressed on thymocytes, most peripheral T cells, and NK cells. CD28 is the ligand for CD80 (B7-1) and CD86 (B7-2) and provides the co-stimulatory signals required for T cell activation and survival. T cell reactivity to antigens is primarily mediated through the CD3/TCR complex, but also depends on the cooperation of other molecules on the T cell surface. Mononuclear cells isolated from peripheral blood, bone marrow, or cord blood can yield large numbers of proliferating T lymphocytes after a period of culture in the presence of CD3 and CD28 monoclonal antibodies and multiple cytokines. This product is a high-purity humanized recombinant monoclonal antibody, expressed in a CHO cell system using completely chemically defined serum-free medium and purified by alkali-tolerant Protein A chromatography, ensuring a truly serum-free, animal-free, adventitious agent-free process that significantly enhances product stability and safety. This product is for research use only.

Product Advantages

• CHO cell-expressed humanized recombinant antibody, animal-free production system

• Chemically defined serum-free culture, alkali-tolerant Protein A chromatography purification

• Targets CD28 (Tp44/T44), the critical co-stimulatory Signal 2 for complete T cell activation

• Synergizes with CD3 antibody (OKT3/UCHT1) to drive robust T lymphocyte proliferation

• High purity ≥ 98% (SDS-PAGE validated)

• High binding activity: ≥ 90% binding to Jurkat cells

• Serum-free, animal-free, adventitious agent-free — enhanced safety and stability

• Pairs with MA1001L-T3 or MA1001L-T1 for the standard CD3/CD28 T cell activation protocol in CAR-T manufacturing

Product Specifications

Figure 1. SDS-PAGE

Figure 2. Binding with Jurkat cell

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 CD3 antibody (OKT3 or UCHT1). 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 CD28 monoclonal antibody (Anti-CD28 mAb) targets the CD28 co-stimulatory molecule on the T cell surface. Full T cell activation requires dual signaling: Signal 1 is provided by the CD3/TCR complex recognizing antigen-MHC, and Signal 2 is provided by CD28 binding to CD80/CD86 (B7 family). In the absence of CD28 signaling, Signal 1 alone leads to T cell anergy or tolerance.

Widely used in:

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

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

• TIL (tumor-infiltrating lymphocyte) manufacturing

• T cell activation and inhibition mechanism studies

• Immune checkpoint and co-stimulatory signal research

• Immunotherapy process development

CD28 co-stimulatory signaling is a cornerstone of T cell immunotherapy. The CD3 + CD28 antibody co-activation system has become the standard protocol for CAR-T manufacturing and T cell expansion. When used alone, it pairs with MA1001L-T3 (OKT3) or MA1001L-T1 (UCHT1).

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.