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 allogeneic 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.