Stress proteins as agents of immunological change: some lessons from metallothionein.

The stress response proteins each have somewhat unique characteristics that enable them to function under conditions of cellular stress, and to contribute to cellular survival in difficult times. The immune response is, by definition, a mechanism that often operates in times of cellular stress, and even creates stress during its operation. Cells called upon to respond to tissue damage caused by inflammation can have extraordinary demands placed upon them and surrounding tissue may suffer damaging conditions that were originally established to eliminate the source of the inflammation. Stress proteins may be released from some of these damaged cells as a programmed response to the stress, or as a simple consequence of excessive damage to the plasma membrane. In either instance, there is the opportunity for these stress proteins to interact with cells and proteins in the extracellular environment. It may be that those same characteristics that enable stress proteins to interact with structures within the cell also enable interactions outside the cell, but with dramatically different results. As has been found with MT, interference with these extracellular interactions may decrease the consequences of stress on the immune response, and may enable more effective immunity. It may also be possible to employ the various stress proteins to manipulate normal immune function.