Human ICOS-expressing Raji Cells

Human ICOS-expressing B cells

Raji-hICOS cells were developed from the human Raji cell line, a human B lymphocyte-derived cell line, and engineered to stably overexpress the human ICOS gene. Raji cells have been successfully used as target cells in human effector studies such as antibody-dependent cellular cytotoxicity (ADCC), either with peripheral blood mononuclear cells, natural killer (NK) cells, or T cell-derived Jurkat reporter cells.

Inducible Co-stimulator (ICOS, CD278) is a  co-stimulatory immune checkpoint (IC) and a member of the CD28 superfamily. Expression of ICOS is rapidly induced in  CD4+ and CD8+ T cells upon their activation, whereas its ligand ICOSL (also known as CD275), is mostly expressed on antigen-presenting cells [1]. The interaction between ICOS and ICOSL delivers a secondary co-stimulatory signal through the activation of the transcription factor AKT, which promotes T cell proliferation and differentiation as well as the production of cytokines  [1]. In tumor immunity, ICOS is involved in the amplification of the anti-tumor cytotoxic CD8+ T cell response, as well as the 'pro-tumor' function and maintenance of regulatory T cells (Tregs). Therefore, both agonistic and antagonistic monoclonal antibodies (mAbs) targeting this pathway are being investigated in combinational cancer immunotherapy [2]. Notably, ICOS agonistic mAbs have been shown to potentiate the effects of anti-CTLA-4 mAbs [3].

Features of Raji-hICOS cells:

• Stable overexpression of the human ICOS gene
• Characterized by a number of cell-surface expressed markers including the B cell receptor (BCR), CD19, and CD20
• Constitutive expression of various immune checkpoints (ICs) such as CD27, CD70, CD80, PD-L1, and 4-1BBL

Applications for Raji-hICOS cells:

• Target cell line for ADCC assays using InvivoGen's Jurkat-Lucia™ NFAT-CD16 cells
• Target cell line for cell toxicity assays using NK or CAR-T cells
• For use in the development of novel human ICOS agonistic and antagonistic mAbs 

Validation of Raji-hICOS cells:

• Overexpression of ICOS verified by flow cytometry
• Functionally tested as target cells in ADCC assays using anti-human ICOS mAbs and Jurkat-Lucia™ NFAT-CD16 cells
• Guaranteed mycoplasma-free

​References:

1. Amatore, F. et al. 2020. Role of ICOS in cancer immunotherapy. Expert Opin Biol Ther 20, 141-150.
2. Solinas, C. et al. 2020. The rationale behind targeting the ICOS-ICOS ligand costimulatory pathway in cancer immunotherapy. ESMO Open 5.
3. Soldevilla, M.M. et al. 2019. ICOS Costimulation at the Tumor Site in Combination with CTLA-4 Blockade Therapy Elicits Strong Tumor Immunity. Mol Ther 27, 1878-1891.