Role of heat shock proteins in protection from and pathogenesis of infectious diseases

Increased synthesis of heat shock proteins (hsp) occurs in prokaryotic and eukaryotic cells when they are exposed to stress. By increasing their hsp c ontent, cells protect themselves from lethal assaults, primarily because hs p interfere with the uncontrolled protein unfolding that occurs under stres s. However, hsp are not produced only by stressed cells; some hsp are synth esized constitutively and perform important housekeeping functions. Accordi ngly, hsp are involved in the assembly of molecules which play important ro les in the immune system. It is nor surprising that due to their wide distr ibution and their homology among different species, hsp represent target an tigens of the immune response. Frequent confrontation of the immune system with conserved regions of hsp which are shared by various microbial pathoge ns can potentiate antimicrobial immunity. However, long-term confrontation of the immune system with hsp antigens which are similar in the host and in vaders may convert the immune response against these host antigens and prom ote autoimmune disease. This review provides an overview of the role of hsp in immunity with a focus on infectious and autoimmune diseases.