Description: The Eat-2 (EAT2) monoclonal antibody reacts with mouse CD81, a molecule also known as TAPA-1. CD81 is expressed on CD4+CD8+ thymocytes and broadly in the periphery with high level expressed by B cells, NK cells, macrophages and dendritic cells and lower level on resting T cells. Activation of T cells induces upregulation of CD81. CD81 is involved in homotypic adhesion of B and T cells as well as costimulation of T cells. The Eat-2 antibody is reported to cross-react with rat CD81.