The present invention provides methods for preventing the allogeneic immune rejection of allogeneic cells, such as cells derived from human Embryonic Stem Cells (hESCs), without suppressing the entire immune system. Also provided a vector containing a CTLA4-Ig and PD-L1 expression cassette, and compositions containing a CTLA4-Ig and PD-L1 for use in preventing allogeneic immune rejection of allogeneic cells.