Abstract

Polymorphisms in the human leukocyte antigen class I genes can cause the rejection of pluripotent stem cell -derived products in allogeneic recipients. Disruption of the Beta-2 Microglobulin gene eliminates surface expression of all class I molecules, but leaves the cells vulnerable to lysis by natural killer cells. Here we show that this 'missing-self' response can be prevented by forced expression of minimally polymorphic HLA-E molecules. We use adeno-associated virus -mediated gene editing to knock in HLA-E genes at the B2M locus in human PSCs in a manner that confers inducible, regulated, surface expression of HLA-E single-chain dimers or trimers, without surface expression of HLA-A, B or C. These HLA-engineered PSCs and their differentiated derivatives are not recognized as allogeneic by CD8+ T cells, do not bind anti-HLA antibodies and are resistant to NK-mediated lysis. Our approach provides a potential source of universal donor cells for applications where the differentiated derivatives lack HLA class II expression.