Inducible Hsp70 as target of anticancer immunotherapy: Identification of HLA‐A*0201‐restricted epitopes

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Abstract
The design of a broad application tumor vaccine requires the identification of tumor antigens expressed in a majority of tumors of various origins. We questioned whether the major stress‐inducible heat shock protein Hsp70 (also known as Hsp72), a protein frequently overexpressed in human tumors of various histological origins, but not in most physiological normal tissues, constitutes a tumor antigen. We selected the p391 and p393 peptides from the sequence of the human inducible Hsp70 that had a high affinity for HLA‐A*0201. These peptides were able to trigger a CTL response in vivo in HLA‐A*0201‐transgenic HHD mice and in vitro in HLA‐A*0201+ healthy donors. p391‐ and p393‐specific human and murine CTL recognized human tumor cells overexpressing Hsp70 in a HLA‐A*0201‐restricted manner. Tetramer analysis of TILs showed that these Hsp70 epitopes are targets of an immune response in many HLA‐A*0201+ breast cancer patients. Hsp70 is a tumor antigen and the Hsp70‐derived peptides p391 and p393 could be used to raise a cytotoxic response against tumors of various origins.
Funding Information
  • INSERM (PROGRES)
  • Ligue Nationale contre le Cancer (Comité de Paris)
  • Association pour la Recherche contre le Cancer (ARC 5129)