Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) binding to CD8 alpha (CD8α) (CEACAM5-CD8α)

Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), commonly known as CEA, is a cell surface glycoprotein and a well-established clinical biomarker for various malignancies, including colorectal and lung cancers (UniProtKB - P06731). Recent research has highlighted its role as a ligand for the CD8 alpha (CD8α) chain, a co-receptor found on cytotoxic T cells (Ordoñez et al., 2007). The binding of CEACAM5 to CD8α can trigger inhibitory signaling pathways that promote the induction of regulatory T cells or suppress the activation of effector T cells, thereby contributing to tumor immune evasion (PubMed: 17513728). This interaction effectively functions as an immune checkpoint within the tumor microenvironment, allowing cancer cells to bypass immunosurveillance. Therapeutic interventions targeting CEACAM5, such as monoclonal antibodies and antibody-drug conjugates like tusamitamab ravtansine, aim to disrupt this immunosuppressive axis or directly target CEA-overexpressing malignant cells (ClinicalTrials.gov). Additionally, bispecific antibodies like cibisatamab are designed to bridge CEA-expressing tumor cells with CD3-expressing T cells, bypassing the inhibitory effects of the CEACAM5-CD8α interaction. Consequently, the CEACAM5-CD8α interaction represents a promising target for enhancing the efficacy of cancer immunotherapies and overcoming resistance in CEA-positive tumors.

Other names

CEA-CD8 interactionCarcinoembryonic antigen binding to CD8 alphaCEACAM5-CD8a complexCEA-CD8a binding

Disruption of the immunosuppressive CEACAM5-CD8α interaction to restore effector T-cell function and enhance anti-tumor immunity.