Our plan is to find ways to facilitate transplants of stem cell-derived cells to genetically different recipients. We propose to inactivate the rejection capability of natural killer cells, a white blood cell type that can reject transplanted cells. To explore this we started with a mouse model. Previously we generated evidence that there are one or more cell types in normal mice can inactivate the rejection capacity of natural killer cells. Our first aim is to identify that cell type to see it can be injected into mice to inactivate the natural killer cells. In the last year we have generated evidence that the relevant cell type is a non-blood cell type. We will now test various non-blood cell types to see which ones have this capability. The hope is that once the cell type has been identified, it could be generated from stem cells and injected into patients to facilitate transplants of other cell types derived from the same stem cells.