Heat shock protein 60: identification of specific epitopes for binding to primary macrophages

In the present study, we characterized regions of human heat shock protein (HSP) 60 responsible for binding to primary macrophages. Studies using 20-mer peptides of the HSP60 sequence to compete with HSP60-binding to macrophages from C57BL/6J mice showed that regions aa241-260, aa391-410 and aa461-480 are involved in surface-binding. HSP60 mutants, lacking the N-terminal 137, 243 or 359 amino acids, inhibited HSP60-binding to primary macrophages to different degrees, demonstrating that all three regions are required for optimal binding. Analysis of different pro- and eukaryotic HSP60 species indicated that phylogenetically separate HSP60 species use different binding sites on primary macrophages.