Hsp70, an immunological actor playing with the intracellular self under oxidative stress.

Heat shock proteins (HSPs) have originally been studied at cellular and molecular levels for their role in resistance to stress. More recently, HSPs have received the attention of immunologists for their ability to stimulate the adaptive and innate immune system. However, the immunological consequences mediated by their expression under stress have not been fully explored. Recent studies on the inducible Hsp70 have promoted the emergence of a new link between oxidative stress and immune response. This view is based on the observation that (i) the stress inducible Hsp70, but not the constitutive Hsc70 co-segregates with immunogenicity of tumour cells in vivo, (ii) the stresses that induce Hsp70 expression also give rise to cellular oxidation, and (iii) an active immune response is a source of oxidative stresses. Here, one explores the hypothesis that, under oxidative stress, Hsp70 is more efficient in discriminating intracellular 'non-self polypeptides' than Hsc70, leading to a more efficient stimulation of the immune system.