Mechanisms of action of monoclonal antibodies in oncology integrated in IMGT/mAb-DB

BackgroundCancer cells activate different immune checkpoint (IC) pathways in order to evade immunosurveillance. Immunotherapies involving ICs either block or stimulate these pathways and enhance the efficiency of the immune system to recognize and attack cancer cells. In this way, the development of monoclonal antibodies (mAbs) targeting ICs has significant success in cancer treatment. Recently, a systematic description of the mechanisms of action (MOA) of the mAbs has been introduced in IMGT/mAb-DB, the IMGT (R) database dedicated to mAbs for therapeutic applications. The characterization of these antibodies provides a comprehensive understanding of how mAbs work in cancer. MethodsIn depth biocuration taking advantage of the abundant literature data as well as amino acid sequence analyses from mAbs managed in IMGT/2Dstructure-DB, the IMGT (R) protein database, allowed to define a standardized and consistent description of the MOA of mAbs targeting immune checkpoints in cancer therapy. ResultsA fine description and a standardized graphical representation of the MOA of selected mAbs are integrated within IMGT/mAb-DB highlighting two main mechanisms in cancer immunotherapy, either Blocking or Agonist. In both cases, the mAbs enhance cytotoxic T lymphocyte (CTL)-mediated anti-tumor immune response (Immunostimulant effect) against tumor cells. On the one hand, mAbs targeting co-inhibitory receptors may have a functional Fc region to increase anti-tumor activity by effector properties that deplete T-reg cells (Fc-effector function effect) or may have limited Fc gamma R binding to prevent T-eff cells depletion and reduce adverse events. On the other hand, agonist mAbs targeting co-stimulatory receptors may bind to Fc gamma Rs, resulting in antibody crosslinking (Fc gamma R crosslinking effect) and substantial agonism. ConclusionIn IMGT/mAb-DB, mAbs for cancer therapy are characterized by their chains, domains and sequence and by several therapeutic metadata, including their MOA. MOAs were recently included as a search criterion to query the database. IMGT (R) is continuing standardized work to describe the MOA of mAbs targeting additional immune checkpoints and novel molecules in cancer therapy, as well as expanding this study to other clinical domains.

Automated summary

Cancer cells activate immune checkpoint pathways to evade immunosurveillance, and immunotherapies involving immune checkpoints have shown significant success in cancer treatment. The IMGT/mAb-DB database provides a standardized and comprehensive description of the mechanisms of action of monoclonal antibodies targeting immune checkpoints in cancer therapy.