CD5 molecule (CD5)

CD5 (Cluster of Differentiation 5) is a 67 kDa type I transmembrane glycoprotein primarily expressed on the surface of mature T cells and a small subset of B cells known as B-1 cells. It belongs to the scavenger receptor cysteine-rich (SRCR) superfamily and serves as a critical negative regulator of T-cell receptor (TCR) and B-cell receptor (BCR) signaling, thereby playing a vital role in maintaining immune tolerance and preventing autoimmunity (UniProt P06127). In recent years, CD5 has emerged as a key target for in situ cell engineering using targeted lipid nanoparticles (tLNPs). These tLNPs are conjugated with anti-CD5 ligands, such as monoclonal antibodies or single-chain variable fragments (scFvs), to facilitate the selective delivery of mRNA payloads directly to T cells within the body (Rurik et al., Science 2022). This technology, exemplified by therapeutic candidates like CPTN-101, aims to produce transient in vivo CAR-T cells for treating conditions such as cardiac fibrosis and hematologic malignancies without the need for complex ex vivo manufacturing. Beyond its role in tLNP delivery, CD5 is also a target for immunotoxins and monoclonal antibodies in the treatment of T-cell lymphomas and chronic lymphocytic leukemia (PubMed: 35000965).

Other names

T-cell surface glycoprotein CD5LEU1T1Ly-1Cluster of Differentiation 5

Receptor-mediated endocytosis of targeted lipid nanoparticles (tLNPs) upon binding to CD5, facilitating the delivery of mRNA payloads (e.g., CAR mRNA) for in vivo T-cell engineering; also targeted for depletion of malignant cells via immunotoxins or antibody-dependent cellular cytotoxicity.