In response to a variety of ''emergencies,'' cells produce several str
ess proteins (heat shock proteins, HSP) that provide them with higher
resistance and are able to repair protein damage. Their expression is
regulated by heat shock transcription factors. Stress proteins are aro
using growing interest in medicine, as major antigens in some infectio
ns and certain autoimmune diseases and also because of their possible
involvement in the development and therapy of cancer. Elevated levels
of stress proteins protect tissues and organs against ischemic injury
and reduce infarct size. Stress proteins may also serve as a marker in
diagnostic studies and in toxicology.