Proteins & Enzymes for Cell Therapy

MHC Complexes, CAR-T Targets, VLPs, Cytokines, and Laminin 521


Cell therapy includes immunocellular therapy and stem cell therapy. It utilizes cells from the patient or a donor, which, after being cultured, expanded, activated, or genetically edited ex vivo, are reinfused into the patient. This stimulates or enhances the body's immune function, thereby achieving a method of controlling diseases. Based on different mechanisms of action, typical types of cell therapy include CAR-T, TILs, TCR-T, CAR-NK, etc.

Figure 1. General Process of Immunocellular Therapy [1][2].

KACTUS Proteins for Cell Therapy Development

Supporting you from discovery through manufacturing.

Immunization Proteins for Drug Discovery

During the drug discovery phase of cell therapy, especially for reprogrammed cell therapeutic drugs, such as immune cells loaded with CAR (Chimeric Antigen Receptor), it is often necessary to obtain the correct scFv (Single-chain Variable Fragment) sequence through immunization with relevant target antigen proteins. This enables the drug product cells to accurately identify tumor cells expressing antigens. KACTUS offers a series of high-quality target antigen protein options for customers to choose from.

MHC Complexes

Intracellular antigen targets are a major direction in cell therapy. Peptide segments, resulted from the degradation of intracellular antigens, form complexes with MHC and are presented on the cell surface for TCR recognition. Targeting MHC peptide complexes can achieve the killing of tumor cells.

KACTUS peptide-MHC complexes cover a variety of popular targets, and include monomers, tetramers, fluorescently-labeled tetramers, and other forms, which can be used for immunization or screening research in the development of T-cell therapeutic drugs. KACTUS also offers custom MHC expression, custom TCR expression, and peptide-ready MHCs to build your own peptide-MHC in house.

Figure 2. Through ELISA and SPR experiments, we have verified that the monomer of HLA-A*02:01&B2M&AFP (FMNKFIYEI) complex can bind separately with Anti-AFP (HLA-A*02:01) Antibody and HLA-A*02:01&B2M&AFP TCR. The EC50 and affinity constant are 7.6 ng/mL and 0.923 μM, respectively.

Figure 3. (Left) Through ELISA validation, it has been confirmed that gp100 TCR & CD3 scfv fusion protein can bind to the monomer of HLA-A*02:01&B2M&GP100 (YLEPGPVTA) complex, with an EC50 of 11.8 ng/mL. (Right) In the SPR analysis, gp100 TCR & CD3 scfv fusion protein can bind to the tetramer of the HLA-A*02:01&B2M&GP100 (YLEPGPVTA) complex, with an affinity constant of 0.196 nM.

CAR-T Target Proteins

KACTUS' high-activity CAR-T target proteins can be applied during the early animal immunization stage for antibody discovery.

Figure 4. CAR-T target proteins, Human CD19 and Human CD7 proteins, can both bind well with the corresponding antibodies.

VLP SuperAntigens

Cell therapy targets include multiple transmembrane proteins (such as the GPCR family) and some targets for which it is difficult to obtain ideal antibody sequences through direct immunization. Our virus-like particle (VLP) display technology can maintain the correct conformation of multiple transmembrane proteins while enhancing the immunogenicity of the protein. In addition, the VLP framework can be designed specifically for your antigen with our custom VLP services.

Browse Cell Therapy Products by Category


Soluble TCR Expression

Custom Service


CAR-T Target Proteins


Gene Editing Enzymes

Cas9 & Cas12a


MaxNuclease, GMP



Laminin 521


Cell Therapy Proteins

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[1] Fang KK, Lee JB, Zhang L. Adoptive Cell Therapy for T-Cell Malignancies. Cancers (Basel). 2022 Dec 23;15(1):94.

[2] Mangal JL, Handlos JL, Esrafili A, Inamdar S, Mcmillian S, Wankhede M, Gottardi R, Acharya AP. Engineering Metabolism of Chimeric Antigen Receptor (CAR) Cells for Developing Efficient Immunotherapies. Cancers (Basel). 2021 Mar 5;13(5):1123.

[3] Maalej KM, Merhi M, Inchakalody VP, Mestiri S, Alam M, Maccalli C, Cherif H, Uddin S, Steinhoff M, Marincola FM, Dermime S. CAR-cell therapy in the era of solid tumor treatment: current challenges and emerging therapeutic advances. Mol Cancer. 2023 Jan 30;22(1):20.