Monoclonal antibody K312-based depletion of pluripotent cells from differentiated stem cell progeny prevents teratoma formation

Abstract

Human pluripotent stem cells (PSCs) have been utilized as a promising source in regenerative medicine. However, the risk of teratoma formation that comes with residual undifferentiated PSCs in differentiated cell populations is most concerning in the clinical use of PSC derivatives. Here, we report that a monoclonal antibody (mAb) targeting PSCs could distinguish undifferentiated PSCs, with potential teratoma-forming activity, from differentiated PSC progeny. A panel of hybridomas generated from mouse immunization with H9 human embryonic stem cells (hESCs) was screened for ESC-specific binding using flow cytometry. A novel mAb, K312, was selected considering its high stem cell-binding activity, and this mAb could bind to several human induced pluripotent stem cells and PSC lines. Cell-binding activity of K312 was markedly decreased as hESCs were differentiated into embryoid bodies or by retinoic acid treatment. In addition, a cell population negatively isolated from undifferentiated or differentiated H9 hESCs via K312 targeting showed a significantly reduced expression of pluripotency markers, including Oct4 and Nanog. Furthermore, K312-based depletion of pluripotent cells from differentiated PSC progeny completely prevented teratoma formation. Therefore, our findings suggest that K312 is utilizable in improving stem cell transplantation safety by specifically distinguishing residual undifferentiated PSCs.

In vitro systems to study inborn errors of immunity using human induced pluripotent stem cells

“…To further minimize the tumorigenic risk, in the last two decades, several systems have been developed for the elimination of aberrant cells using suicide gene technology ( 103 – 108 ). Most recently, immunodepletion has also been used to selectively deplete contaminating iPSCs with the help of monoclonal antibodies ( 109 , 110 ) or chimerized monoclonal antibodies ( 111 ). Further optimization of these tools will significantly assist in facilitating the safe use of iPSC-derived cells in the clinical setting in the future.…”

Fc engineered anti‐virus therapeutic human IgG1 expressed in plants with altered binding to the neonatal Fc receptor

“…Monoclonal antibodies (mAb) of the IgG type have played an important role in therapeutic proteins for the treatment of many human diseases, such as autoimmune diseases, cancers, and virus diseases. [1,2] In humans, a serum half-life of IgG 1 is about 21 days, whereas IgM and IgA persist for only 5-8 days. [3] The persistence of IgG is regulated by the neonatal Fc receptor (FcRn) [4,5] recycling pathway, which salvages IgG from lysosomal degradation within cells.…”