Heat shock proteins [ called Heat shock proteins , HSP ] are proteins having the amino acid sequence of the most conservative in the biosphere . Play an important role in all prokaryotic and eukaryotic cells , protecting them from the harmful consequences of metabolic and environmental factors. Act as agents for the care of other proteins involved in folding of the polypeptide chains and de-interleaving , oligomerisation , translocation and degradation . HSP belong to several families , where they were classified according to their molecular weight , m.in: HSP100 (family 100 - kDa) , HSP90 (family 90 - kDa) , HSP70 (family 70 - kDa) , HSP60 ( 60 - kDa family ) and HSP20 ( 18-30 kDa). Expression of HSP -encoding genes induces cell exposure to high temperatures and other exogenous and endogenous factors , called molecular stressors may be: amino acid analogues , heavy metals , alcohol , free radicals, many metabolic poisons , viral and bacterial infection , the shortage of glucose, cytokine UV radiation and others. In this article the general characteristics of HSPs and their role in modulating the immune response and the possible association with many disease states.