Using an in vitro model of polymyositis (co-culture of CD8+ T cells with C2C12 myotubes transduced retrovirally with the genes encoding major histocompatibility complex (MHC) class I and a peptide derived from ovalbumin), it was shown that CD8+ T cells invade myotubes and contribute to muscle damage [115]. The gene discussed is CD8A; the disease is polymyositis.