XL166

XL166 is a monoclonal antibody that selectively recognizes the RGDAPG cryptic epitope of type-I collagen. It was developed as part of a series of antibodies designed to investigate biomechanical extracellular matrix (ECM) switches, which are localized changes in the ECM that expose hidden binding sites during tumor growth and inflammation. While related antibodies such as XL313 have demonstrated the ability to inhibit angiogenesis and tumor progression by targeting specific collagen elements, XL166 has shown no significant effect on tumor growth, angiogenesis, or inflammation in preclinical models, including the Chick CAM assay and B16F10 melanoma models. Consequently, XL166 is primarily utilized as a research tool or negative control to differentiate the functional roles of various RGD-containing sequences within the collagen matrix.