Interaction of human heat shock protein 70 with tumor-associated peptides.
Molecular chaperones of the heat shock protein 70 (Hsp70) family play a crucial role in the presentation of exogenous antigenic peptides by antigen-presenting cells (APCs). In a combined biochemical and immunological approach, we characterize the biochemical interaction of tumor-associated peptides with human Hsp70 and show that the strength of this interaction determines the efficacy of immunological cross-presentation of the antigenic sequences by APCs. A fluorescein-labeled cytosolic mammalian Hsc70 binding peptide is shown to interact with human Hsp70 molecules with high affinity (K(d) = 0.58 microm at 25 degrees C). Competition experiments demonstrate weaker binding by Hsp70 of antigenic peptides derived from the tumor-associated proteins tyrosinase (K(d) = 32 microm) and melanoma antigen recognized by T cells (MART-1) (K(d) = 2.4 microm). Adding a peptide sequence (pep70) with high Hsp70 binding affinity (K(d) = 0.04 microm) to the tumor-associated peptides enables them to strongly interact with Hsp70. Presentation of tumor-associated peptides by B cells resulting in T cell activation in vitro is enhanced by Hsp70 when the tumor-associated peptides contain the Hsp70 binding sequence. This observation has relevance for vaccine design, as augmented transfer of tumor-associated antigens to APCs is closely linked to the vaccine's efficacy of T cell stimulation.
Pandya
Maya J
MJ
Department of Internal Medicine III, Klinikum Grosshadern Medical Center, Ludwig Maximilians University, D-81377 Munich, Germany and Department of Chemistry, Munich Technical University, D-85747 Garching, Germany. M.Pandya@sheffield.ac.uk
Bendz
Henriette
H
Manzenrieder
Florian
F
Noessner
Elfriede
E
Kessler
Horst
H
Buchner
Johannes
J
Issels
Rolf D
RD
D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
D000951:Antigens, Neoplasm; D018840:HSP70 Heat-Shock Proteins; D011994:Recombinant Proteins