Autologous SIRPa-depleted Activated Macrophages SI-101

**Semantic type:** Cell|Pharmacologic Substance

**Definition:** A preparation of autologous macrophages that are ex vivo activated and depleted of signal-regulatory protein alpha (SIRP-alpha; SIRPa; CD172a), with potential immunostimulatory and antineoplastic activities. Upon reintroduction into the patient, autologous SIRPa-depleted activated macrophages SI-101 elicits an anti-tumor immune response via the phagocytosis of tumor cells. In addition, the autologous SIRPa-depleted activated macrophages SI-101 promotes a pro-inflammatory tumor microenvironment (TME) and activates a cancer neoantigen-specific cytotoxic T-lymphocyte (CTL)-mediated anti-tumor immune response. The depletion of SIRPa, an inhibitory protein expressed on macrophages and dendritic cells (DCs), prevents SIRPa/CD47-mediated inhibition of macrophage activity.

**Synonyms:** - Autologous SIRPa-low Macrophages SI-101 - SI 101 - SI-101 - SI101 - SIRPant-M