SIRPα/CD47 Blockade Bioassay, Propagation Model Technical Manual
Instructions for Use of Product(s)
JA6012, GA6040
Literature # TM698
Phagocytosis is regulated by a complex network of checkpoints that facilitates removal of aberrant or infected cells while preserving healthy tissues. CD47, a “marker-of-self” protein expressed on virtually all cell types, engages the myeloid-specific receptor signal regulatory protein alpha (SIRPα) to prevent phagocytosis of healthy cells. Despite its important physiological role, this SIRPα/CD47 checkpoint contributes to immune escape by tumor cells, many of which overexpress CD47 and thereby evade phagocytosis. Biologics that inhibit SIRPα/CD47 interaction enhance phagocytosis of tumor cells in vitro and have shown promising therapeutic efficacy. Given the broad expression of CD47 in vivo, many biologics targeting the SIRPα/CD47 checkpoint are engineered to ablate or eliminate FcγR-binding (i.e., Fc-silent or Fc-null) to minimize on-target, off-tumor toxicities.
The SIRPα/CD47 Blockade Bioassay, Propagation Model, is a bioluminescent reporter cell-based assay that overcomes the limitations of existing assays. The bioassay is easy-to-use, quantitative and demonstrates the functional response of SIRPα/CD47 inhibitors. It can be used to measure the potency and stability of Fc-silent antibodies and other Fc-null biologics that block SIRPα/CD47 interaction.
Summary of Changes
The following changes were made to the 5/25 revision of this document:
1. Removed an expired patent statement.
2. Revised text about the label in Section 3.
Revised 5/25.