Variation in MHC Expression Between Undifferentiated Mouse ES Cells and ES Cell-derived Insulin-producing Cell Clusters

Background. The progeny of embryonic stem (ES) cells may eventually be used to replace damaged tissues in transplantation, yet their immunogenicity remains ill-defined. The major histocompatibility complex (MHC) is a determinant of immunogenicity in transplantation. Methods and Results. Herein, we show differences in MHC expression between mouse ES cells and ES cell derived insulin producing cell clusters (IPCCs), including a relatively higher expression of MHC Class I in IPCCs and a faster, more dramatic induction of MHC Class I in IPCCs following challenge with interferon-gamma (IFN-gamma). MHC Class II was induced on IPCCs, but not ES cells, after exposure to IFN-gamma. Transplantation of syngeneic or atlogeneic IPCCs was insufficient to trigger Up-regulation of MHC class I within three days after transplantation. Discussion. These data highlight differences in MHC expression between ES cells and a fully differentiated ES cell derived tissue and suggest how the progeny of ES cells may be susceptible to rejection after transplantation.