SEMA4D

Class

Anti-SEMA4D monoclonal antibody

SEMA4D (also called CD100) is a transmembrane signaling protein belonging to the semaphorin family, originally characterized for its role in guiding axon growth during nervous system development. It is also expressed on activated immune cells and can be cleaved from the cell surface to act as a soluble signaling molecule. Physiologically, SEMA4D helps orchestrate cell migration, tissue patterning, and immune cell communication. In disease, however, its signaling can become counterproductive: in neurodegenerative conditions it appears to interfere with the maturation of cells responsible for rebuilding myelin, the insulating sheath around nerve fibers, and in tumors it contributes to an immunosuppressive microenvironment that limits immune cell infiltration. Blocking SEMA4D with a monoclonal antibody is intended to remove this inhibitory signal, creating conditions more favorable to neural repair or to an effective anti-tumor immune response. Because SEMA4D sits at the intersection of neurobiology and immunology, antibodies against it are being explored across two quite different therapeutic contexts: neurodegenerative disease, where the goal is to support remyelination, and oncology, where the goal is to convert immunologically inactive tumors into ones accessible to immune attack, often alongside other immune-modulating therapies.