INCREASED INTERFERON-GAMMA-MESSENGER-RNA EXPRESSION FOLLOWING ALLOINCOMPATIBLE MYOBLAST TRANSPLANTATION IS INHIBITED BY FK506

Myoblasts from C57BL/10SnJ+/+ were transplanted in major histocompatib ility complex (MHC)-compatible mice (i.e., C57BL10SnJ+/+ and C57BL/10S nSc mdx/mdx) and in MHC-noncompatible (BALB/c+/+) mice. The recipients were killed 1-21 days after transplantation. C57BL10SnJ+/+ myoblasts were also transplanted in a few BALB/c+/+ mice treated with FK506 and killed 7 days thereafter. Our results showed that after MHC-noncompati ble transplantation, interferon-gamma (IFN-gamma) mRNA expression is i ncreased from day 5 to day 21, indicating the presence of a cellular i mmune reaction. Short-term immunosuppressive treatment with FK506 inhi bited the transcription of IFN-gamma mRNA compared with that in untrea ted mice. Myoblast-specific antibodies were also detected 2 and 3 week s after MHC-incompatible transplantation, indicating that the cellular immune reaction, revealed by the increase in IFN-gamma, was followed by a humoral reaction. (C) 1996 John Wiley & Sons, Inc.