Background

The observation that heat shock proteins isolated from cancers of mice and rats elicited specific immunity to the cancers from which they were derived, led to the discovery that heat shock proteins are associated with peptides, including antigenic peptides 1. These peptides, in association with the heat shock proteins, elicited potent and specific T cell immunity to the cells that presented them. The mechanism behind this phenomenon turned out to be pretty much as it was originally proposed 2, 3. Across species, heat shock proteins are the most highly conserved group of molecules, as is the receptor for at least one of them 4, and so a key question was whether heat shock protein–peptide complexes could elicit protective immunity to human cancers.