Human Anti-SSEA4 Recombinant Antibody (HPAB-N0258-YC) (CAT#: HPAB-N0258-YC)

Gravina, Alessia, et al. "Synthetic immune checkpoint engagers protect HLA-deficient iPSCs and derivatives from innate immune cell cytotoxicity." Cell Stem Cell 30.11 (2023): 1538-1548. https://doi.org/10.1016/j.stem.2023.10.003

This research introduces a novel approach to protecting cell therapeutics from immune rejection through synthetic immune checkpoint engagers. The scientists designed agonistic cell surface molecules that activate inhibitory receptors on immune cells, preventing them from attacking transplanted cells. These engineered molecules target different immune checkpoint pathways including TIM3 and SIRPα on natural killer cells and macrophages. By combining the SIRPα engager with truncated CD64, they created fully immune-evasive cells that escape both cellular rejection and antibody-mediated attacks. The researchers demonstrated that these engineered cells survived in stringent in vitro and in vivo models, showing complete protection against all allogeneic immune responses including antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity.
Creative Biolabs provided both humanized anti-MICA IgG1 antibodies (CAT# TAB-0799CL) and humanized anti-SSEA-4 IgG1 antibodies (CAT# HPAB-N0258-YC). These antibodies were essential for testing the protective capabilities of the engineered cells against different forms of antibody-mediated killing. The anti-MICA antibodies were used in the main NK cell-mediated ADCC experiments, while the anti-SSEA-4 antibodies were used to evaluate CDC and ADCC protection in the B2M-KO iPSCs. These well-characterized humanized antibodies enabled comprehensive evaluation of the immune evasion strategy, demonstrating that cells expressing both the SIRPα engager and truncated CD64 provide protection against multiple immune attack mechanisms, which is critical for advancing allogeneic cell therapeutics toward clinical applications.