title: HSP70 peptide binding mutants separate antigen delivery from dendritic cell stimulation.
abstract: Microbial heat shock proteins (HSPs) have been implicated in the induction of both the innate and adaptive arms of the immune response. We now show that human dendritic cells (DC) pulsed with peptide-loaded mycobacterial HSP70 complexes generate potent antigen-specific cytotoxic lymphocyte (CTL) responses, which are dependent on an HSP70-stimulated calcium signaling cascade. From the calculated peptide binding affinity of mycobacterial HSP70 (K(D) = 14 microM) we show that 120 pM HSP70 bound peptide is sufficient to generate a peptide-specific CTL response that is up to four orders of magnitude more efficient than peptide alone. The minimal 136 amino acid, mycobacterial HSP70 peptide binding domain can generate CTL responses, and a single amino acid mutant HSP70 designed to prevent peptide binding but retain stimulatory capacity has allowed us to separate antigen delivery from DC immunostimulation.
authors.affiliation: Division of Immunology, Department of Medicine, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Hills Road, CB2 2XY, Cambridge, United Kingdom.
authors.forename: Paul A
authors.initials: PA
authors.lastname: MacAry
authors.forename: Babak
authors.initials: B
authors.lastname: Javid
authors.forename: R Andres
authors.initials: RA
authors.lastname: Floto
authors.forename: Kenneth G C
authors.initials: KG
authors.lastname: Smith
authors.forename: Wulf
authors.initials: W
authors.lastname: Oehlmann
authors.forename: Mahavir
authors.initials: M
authors.lastname: Singh
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lehner
mesh_terms: D000818:Animals; D000941:Antigens / Q000276:immunology*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D009154:Mutation; D009161:Mycobacterium / Q000276:immunology; D010455:Peptides / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000941:Antigens; D018840:HSP70 Heat-Shock Proteins; D010455:Peptides; D002118:Calcium