CD44 & CD3

CD44 is a transmembrane glycoprotein involved in cell adhesion, migration, and signaling, binding hyaluronic acid (HA) and other extracellular matrix molecules. Expressed ubiquitously on normal cells (hematopoietic, epithelial, stromal), it is overexpressed and aberrantly glycosylated in many solid tumors (breast, colon, prostate) and hematologic cancers. CD44+ cancer cells often exhibit stem cell-like properties (tumor-initiating cells), contributing to metastasis, chemoresistance, and recurrence. It is a target for monoclonal antibodies, ADCs, and peptide vaccines, aiming to inhibit tumor cell migration and eliminate cancer stem cells.

In immunology, the CD3 (cluster of differentiation 3) T-cell co-receptor is a protein complex and is composed of four distinct chains. In mammals, the complex contains a CD3γ chain, a CD3δ chain, and two CD3ε chains. These chains associate with a molecule known as the T-cell receptor (TCR) and the ζ-chain to generate an activation signal in T lymphocytes. The TCR, ζ-chain, and CD3 molecules together comprise the TCR complex.