Basic principles

Figure 2: In complex organisms, programs of stress genes expression (circles) overlap with one and another, with the exception of the heat shock and acute-phase responses. Genes characteristic of the four responses are shown in italics. HSP72, heat shock protein-72 kilodalton molecular weight. [Buc94]

At the cellular level the cell has only a few basic responses to external stresses[Buc94]. These are the heat shock response, the oxidative stress response and the ultraviolet damage response. A fourth response termed the acute phase response is only seen in multicellular organisms and may have developed to coordinate the response of a variety of cell types to an external threat, see figure 2. Endothelial cells, macrophages (monocytes) and epithelial cells are involved in this complex response. Exaggeration of the acute phase response results in the sepsis-syndrome which is the predecessor of multi-organ failure.