Diversity of physiological cell reactivity to heat shock protein 60 in different mouse strains

Heat shock proteins (Hsp) are families of highly conserved molecules and immunodominant antigens in some infections and in autoimmune diseases. Some reports suggest that different regions of the Hsp60 molecule induce distinct immune responses. However, there are no reports comparing physiological T-cell reactivity to Hsp60 in mice. In this study, we have analyzed T-cell proliferation and cytokine production induced by Hsp60, under physiological conditions, in three mouse strains bearing distinct major histocompatibility complex (MHC) backgrounds. Proliferative response predominantly was found in C57BL/6 mice, mostly induced by N-terminal and intermediate Hsp60 peptides (P < 0.0001). Interferon-gamma (IFNgamma) production was broadly induced by different regions of Hsp60 in all three mouse strains, although response was focused in different peptide groups in each strain. We did not observe an exclusive Th1 or Th2 cytokine profile induced by any particular region of Hsp60. However, we identified a strain hierarchy in IL-10 production induced by Hsp60 peptides from different regions, mostly detected in C3H/HePas, and in BALB/c, but not in C57BL/6 mice. In contrast, IL-4 production only was induced by the intermediate and C-terminal region peptides in both C3H/HePas and BALB/c mice. Our data give original information on physiological cellular reactivity to Hsp60. We also have identified peptides with the capacity to induce the production of anti-inflammatory cytokines, bringing perspectives for their use in immunotherapy of chronic inflammatory diseases and allograft rejection.