Production and characterization of a monoclonal antibody specific to the human 70-kDa heat shock protein

Heat shock protein 70 (hsp 70) plays major roles in apoptosis prevention an d thermotolerance as well as molecular chaperoning. It is also expressed on the surface of human tumor cells, but not on normal cells, suggesting that hsp70 may be some tumor-associated antigen. To investigate the diverse fun ctions of the protein species, various types of transgenic mice or cell mod els overexpressing human hsp70 have been made. In these models a monoclonal antibody (MAb) specific for the human hsp70 is highly desirable to disting uish the human from the endogenous mouse hsp70. It proved difficult to make this species-specific MAb, because the hsp70 homologues are members of a f amily of highly conserved, abundant, and ubiquitous proteins expressed in o rganisms ranging from bacteria to humans. In the present study, we prepared four MAbs against human hsp70. Three, HD 5, HD 7 and HD 11, recognize huma n and mouse hsp70. One, though, HD 8, recognizes human hsp70, but not mouse hsp70. By Western blot analysis of hsp70 deletion mutants, the epitope of the HD 8 MAb was determined as the 585-616 amino acid region of the human h sp70, a region with relatively low homology to mouse hsp70.