Product(s) used in this publication: PepSpots™ Peptides on Cellulose
Heatshockprotein70 (HSPA) is a molecular chaperone which has been suggested to shuttle human leukocyte antigen (HLA) epitopeprecursors from the proteasome to the transporter associated with antigen processing. Despite the reported observations that peptides chaperoned by HSPA are an effective source of antigens for cross-priming, little is known about the peptides involved in the process. In this study, we investigated the possible involvement of HSPA in HLAclass I or classII antigen presentation and analysed the antigenic potential of the associated peptides. HSPA was purified from CCRF-CEM and K562 cell lines, and using mass spectrometry techniques, we identified 44 different peptides which were co-purified with HSPA. The affinity of the identified peptides to two HSPA isoforms, HSPA1A and HSPA8, was confirmed using a peptide array. Four of the HSPA-associated peptides were matched with 13 previously reported HLA epitopes. Of these 13 peptides, nine were HLAclass I and four were HLAclassII epitopes. These results demonstrate the association of HSPA with HLAclass I and classII epitopes, therefore providing further evidence for the involvement of HSPA in the antigen presentation process.