Control Raji Cells

Control Human B-cell line

Raji-Null cells were developed from the human Raji cell line. Raji-Null cells constitutively express different antigens at their cell surface that can be targeted by specific antibodies, notably to induce antibody-dependent cellular cytotoxicity (ADCC).

-Human CD20 is highly expressed by Raji cells. It has no known natural ligand and is thought to act as calcium channel enabling optimal B-cell responses [1]. Human CD20 is a clinically-relevant target in mAb-mediated therapy (rituximab, ofatumumab, obinutuzumab) for non-Hodgkin's B cell lymphoma or chronic lymphocytic leukemia [2].

-Human CD19 is highly expressed by Raji cells. It acts as a co-receptor decreasing the threshold for antigen B-cell receptor (BCR)-dependent stimulation [1]. Human CD19 is a clinical target for anti-hCD19-CD3 bis-specific antibodies (blinatumomab) in non Hodgkin's B cell lymphoma [3].

- Human PD-L1 (programmed cell death ligand 1; also known as CD274 or B7-H1) is expressed at low levels by Raji cells. This transmembrane protein is expressed by hematopoietic and nonhematopoietic cells and is induced by pro-inflammatory cytokines, such as in the tumor microenvironment [4]. Human PD-L1 is a clinically-relevant target in mAb-mediated therapy (atezolizumab, durvalumab, avelumab) for a wide range of cancers [4].

Features of Raji-Null cells:

• Constitutive expression of CD19 and CD20 at the cell surface
• Constitutive low expression of PD-L1 at the cell surface
• Stable expression of a resistance gene to Blasticidin

Applications for Raji-Null cells:

• ADCC target cells using anti-hCD19, anti-hCD20, anti-hPD-L1 Abs
• Negative control target cells in ADCC assays using monoclonal Abs other than anti-hCD19, anti-hCD20, anti-hPD-L1 Abs
• Target cells for anti-hCD19-CD3 bispecific Abs

Validation of Raji-Null cells:

• Functionally tested as target cells in ADCC assays using anti-human CD20 monoclonal Abs and Jurkat-Lucia™ NFAT-CD16 cells
• Functionally tested as negative control target cells in ADCC assays using monoclonal Abs other than anti-hCD20 (e.g. anti-hCTLA-4 or anti-hPD-1 Abs)
• Functionally tested as target cells in T-cell activation assay using anti-hCD19-CD3 bi-specific Ab and Jurkat-Lucia™ NFAT cells.

References:

1. Bae J. et al. 2005. Identification of CD19 and CD20 peptides for the induction of antigen-specific CTLs against B-cell malignancies. Clin. Cancer. Res. 11:1629-38.
2. Almagro J.C. et al. 2018. Progress and challenges in the development of antibodies for cancer therapy. Front. Immunol. 8:1751.
3. Bargou R. et al. 2008. Tumor regression in cancer patients by very low doses of a T cell-engaging antibody. Science. 321(5891):974-7.
4. Ribas A. and Wolchock J.D., 2018. Cancer immunotherapy using checkpoint blockade. Science. 359:1350-55.