Skip to main content
An official website of the United States government
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

anti-SIRPa monoclonal antibody DS-1103

An immunoglobulin G4 (IgG4) monoclonal antibody targeting human signal-regulatory protein alpha (SIRPa; CD172a), with potential immune checkpoint inhibitory, phagocytosis-inducing and antineoplastic activities. Upon administration, anti-SIRPa monoclonal antibody DS-1103 targets and binds to SIRPa, a cell surface protein expressed on macrophages, thereby blocking the interaction between SIRPa and cluster of differentiation 47 (CD47) expressed on tumor cells. This prevents CD47/SIRPa-mediated signaling and abrogates the CD47/SIRPa-mediated inhibition of phagocytosis. This induces pro-phagocytic signaling mediated by the binding of calreticulin (CRT), which is specifically expressed on the surface of tumor cells, to low-density lipoprotein (LDL) receptor-related protein (LRP), expressed on macrophages, and results in macrophage activation and the specific phagocytosis of tumor cells. SIRPa, also known as tyrosine-protein phosphatase non-receptor type substrate 1, mediates negative regulation of phagocytosis, mast cell activation and dendritic cell activation. CD47, also called integrin-associated protein (IAP), is a tumor-associated antigen (TAA) expressed on normal, healthy hematopoietic stem cells (HSCs) and overexpressed on the surface of a variety of cancer cells. Expression of CD47, and its interaction with SIRPa, leads to the inhibition of macrophage activation and protects cancer cells from phagocytosis, which allows cancer cells to proliferate.
Synonym:anti-SIRPalpha monoclonal antibody DS-1103
Code name:DS 1103
DS 1103a
DS-1103
DS-1103a
DS1103
DS1103a
Search NCI's Drug Dictionary