A 14-mer Hsp70 peptide stimulates natural killer (NK) cell activity.
Compared with normal cells, tumor cell lines exhibit an unusual plasma membrane localization of heat shock protein 70 (Hsp70). This tumor-selective Hsp70 membrane expression has been found to correlate with an increased sensitivity to lysis mediated by human natural killer (NK) cells that transiently adhere to plastic following cytokine stimulation. A human Hsp70-specific monoclonal antibody (mAb) detects membrane-bound Hsp70 on viable tumor cells and blocks the immune response of NK cells against Hsp70-expressing tumor cells. By peptide scanning (pep-scan) analysis, the epitope of this mAb was mapped as the C-terminal-localized 8-mer NLLGRFEL (NLL, amino acids [aa] 454-461). Most interestingly, similar to full-length Hsp70 protein, the N-terminal-extended 14-mer peptide TKDNNLLGRFELSG (TKD, aa 450-463) was able to stimulate the cytolytic and proliferative activity of NK cells at concentrations equivalent to full-length Hsp70 protein. Blocking studies revealed that an excess of the 14-mer peptide TKDNNLLGRFELSG inhibits the cytolytic activity of NK cells similar to that of Hsp70 protein. In comparison, other TKD-related peptides, including the 8-mer antibody epitope NLLGRFEL (aa 454-461), the 12-mer TKDNNLLGRFEL (aa 450-461), the 13-mer C-terminal-extended peptide NLLGRFELSGIPP (aa 454-466), the 14-mer TKD-equivalent sequences of Hsp70hom TKDNNLLGRFELTG (aa 450-463), Hsc70 TKDNNLLGKFELTG (aa 450-463), and DnaK AADNKSLGQFNLDG (aa 447-460) failed to activate NK activity.
Multhoff
G
G
Department of Hematology and Oncology, University Hospital Regensburg, Germany. Gabriele.Multhoff@klinik.uni-regensburg.de
Pfister
K
K
Gehrmann
M
M
Hantschel
M
M
Gross
C
C
Hafner
M
M
Hiddemann
W
W
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D000939:Epitopes / Q000032:analysis; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D006801:Humans; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D009369:Neoplasms / Q000276:immunology; D010455:Peptides / Q000494:pharmacology; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D016207:Cytokines; D000939:Epitopes; D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; D010455:Peptides; D011994:Recombinant Proteins