The 16B1 monoclonal antibody specifically reacts with human CD144, the 140 kDA molecule called vascular endothelial (VE-cadherin) or cadherin 5. CD144 is an endothelial specific calcium-dependent adhesion molecule involved in cell contact-dependent growth inhibition, migration, survival, adhesion. It is concentrated at the intercellular boundaries of endothelial cells and essential in maintaining cell layer integrity.