| Autor: |
Lombana TN; a Department of Antibody Engineering , Genentech Inc ., South San Francisco , USA., Matsumoto ML; b Structural Biology , Genentech Inc ., South San Francisco , USA., Berkley AM; c Translational Oncology , Genentech Inc ., South San Francisco , USA., Toy E; c Translational Oncology , Genentech Inc ., South San Francisco , USA., Cook R; d Biochemical and Cellular Pharmacology , Genentech Inc ., South San Francisco , USA., Gan Y; e Microchemistry, Proteomics and Lipidomics , Genentech Inc ., South San Francisco , USA., Du C; d Biochemical and Cellular Pharmacology , Genentech Inc ., South San Francisco , USA., Schnier P; e Microchemistry, Proteomics and Lipidomics , Genentech Inc ., South San Francisco , USA., Sandoval W; e Microchemistry, Proteomics and Lipidomics , Genentech Inc ., South San Francisco , USA., Ye Z; d Biochemical and Cellular Pharmacology , Genentech Inc ., South San Francisco , USA., Schartner JM; c Translational Oncology , Genentech Inc ., South San Francisco , USA., Kim J; f Cancer Immunology , Genentech Inc ., South San Francisco , USA., Spiess C; a Department of Antibody Engineering , Genentech Inc ., South San Francisco , USA. |
| Abstrakt: |
As an immune evasion strategy, MICA and MICB, the major histocompatibility complex class I homologs, are proteolytically cleaved from the surface of cancer cells leading to impairment of CD8 + T cell- and natural killer cell-mediated immune responses. Antibodies that inhibit MICA/B shedding from tumors have therapeutic potential, but the optimal epitopes are unknown. Therefore, we developed a high-resolution, high-throughput glycosylation-engineered epitope mapping (GEM) method, which utilizes site-specific insertion of N-linked glycans onto the antigen surface to mask local regions. We apply GEM to the discovery of epitopes important for shedding inhibition of MICA/B and validate the epitopes at the residue level by alanine scanning and X-ray crystallography (Protein Data Bank accession numbers 6DDM (1D5 Fab-MICA*008), 6DDR (13A9 Fab-MICA*008), 6DDV (6E1 Fab-MICA*008). Furthermore, we show that potent inhibition of MICA shedding can be achieved by antibodies that bind GEM epitopes adjacent to previously reported cleavage sites, and that these anti-MICA/B antibodies can prevent tumor growth in vivo. |
