66 – Immunogenicity of Human Embryonic Stem Cells

This chapter outlines the immunological properties of human embryonic stem (ES) cells related to immune rejection processes. In addition, various methodologies to overcome rejection of human ES derived cells are also discussed. The recent introduction of human embryonic stem (hES) cells into the emerging field of cellular transplantation therapeutics has boosted worldwide attention to the potential medical treatments that may be available using these cells. In hES cell therapy, as in organ transplantation, the three most important classes of all oantigens that may cause rejection are the major histocompatibility complex (MHC) antigens, minor histocompatibility complex (mHC) antigens, and ABO blood group antigens. It is known today that hES cells and their differentiated derivatives can be induced to express high levels of MHC-I molecules, which may initiate rejection by either direct or indirect routes. To circumvent this problem, it may be possible in the future to transplant the cells into immune-privileged sites or to build banks of cell lines that would match a high proportion of the population.