Abstract
Purified preparations of selected heat shock proteins (of the hsp90 and hsp70 families) are actually non-covalent complexes of HSPs with peptides that contain the MHC Class I-binding octa/nonamers. Several purified HSP-peptide complexes have been shown to specifically activate the immune system through delivery of the antigenic peptides to antigen-presenting cells (APC) for cross-presentation, but little is known about the formation of intracellular HSP-peptide complexes. The aim of this study is to quantify the relationship between MHC I-binding peptides (and their extended precursors) and chaperone proteins under two immunologically important states: induction of a neoantigen and cellular stress. We present here the development of a novel cell line, PIK23, which employs the modified version of ovalbumin, KOVAK, under the control of a synthetic, inducible promoter system. Using this cell line, we have identified MHC-I binding peptides associated with gp96 and Hsp70, and have begun to quantify these peptides in relation to the translation of the antigenic protein and state of cellular stress.
