Blockade of Tim-3 binding to phosphatidylserine and CEACAM1 is a shared feature of anti-Tim-3 antibodies that have functional efficacy

• Published in: Oncoimmunology 2018-02, Vol.7 (2), p.e1385690-e1385690
• Main Authors: Sabatos-Peyton, Catherine A., Nevin, James, Brock, Ansgar, Venable, John D., Tan, Dewar J., Kassam, Nasim, Xu, Fangmin, Taraszka, John, Wesemann, Luke, Pertel, Thomas, Acharya, Nandini, Klapholz, Max, Etminan, Yassaman, Jiang, Xiaomo, Huang, Yu-Hwa, Blumberg, Richard S., Kuchroo, Vijay K., Anderson, Ana C.
• Format: Article
• Language: English
• Subjects: antibody; checkpoint receptor; HDxMS; ligand; Original Research; Tim-3
• ISSN: 2162-4011; 2162-402X; 2162-402X
• DOI: 10.1080/2162402X.2017.1385690

Both in vivo data in preclinical cancer models and in vitro data with T cells from patients with advanced cancer support a role for Tim-3 blockade in promoting effective anti-tumor immunity. Consequently, there is considerable interest in the clinical development of antibody-based therapeutics that target Tim-3 for cancer immunotherapy. A challenge to this clinical development is the fact that several ligands for Tim-3 have been identified: galectin-9, phosphatidylserine, HMGB1, and most recently, CEACAM1. These observations raise the important question of which of these multiple receptor:ligand relationships must be blocked by an anti-Tim-3 antibody in order to achieve therapeutic efficacy. Here, we have examined the properties of anti-murine and anti-human Tim-3 antibodies that have shown functional efficacy and find that all antibodies bind to Tim-3 in a manner that interferes with Tim-3 binding to both phosphatidylserine and CEACAM1. Our data have implications for the understanding of Tim-3 biology and for the screening of anti-Tim-3 antibody candidates that will have functional properties in vivo.