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Licensed Unlicensed Requires Authentication Published by De Gruyter June 1, 2005

Interaction of Heat Shock Protein 70 Peptide with NK Cells Involves the NK Receptor CD94

  • C. Gross , D. Hansch , R. Gastpar and G. Multhoff
From the journal Biological Chemistry

Abstract

Full-length Hsp70 protein (Hsp70) and the C-terminal domain of Hsp70 (Hsp70C) both stimulate the cytolytic activity of naive natural killer (NK) cells against Hsp70-positive tumor target cells. Here, we describe the characterization of Hsp70-NK cell interaction with binding studies using the human NK cell line YT. Binding of recombinant Hsp70 protein (Hsp70) and the C-terminal domain of Hsp70 (Hsp70C) to YT cells is demonstrated by immunofluorescence studies. A phenotypic characterization revealed that none of the recently described HSP-receptors (α 2-macroglobulin receptor CD91, Toll-like receptors 2, 4, 9, CD14) are expressed on YT cells. Only the C-type lectin receptor CD94 is commonly expressed by YT cells and Hsp70 reactive NK cells. A correlation of the cell density-dependent, variable CD94 expression and the binding capacity of Hsp70 was detected. Furthermore, Hsp70 binding could be completely abrogated by preincubation of YT cells with a CD94-specific antibody. Competition assays using either unlabeled Hsp70 protein or an unrelated protein (GST) in 20-fold excess and binding studies with escalating doses of Hsp70 protein provide evidence for a specific and concentration-dependent interaction of Hsp70 with YT cells. In addition to Hsp70 and Hsp70C, a 14-mer Hsp70 peptide termed TKD is known to exhibit comparable stimulatory properties on NK cells. Similar to fulllength Hsp70 protein (10 ug/ml-50 ug/ml), a specific binding of this peptide to YT cells was observed at 4C, at equivalent concentrations (2.0 ug/ml-8.0 ug/ml). Following a 30 min incubation period at 37C, membrane-bound Hsp70 protein and Hsp70 peptide TKD were completely taken up into the cytoplasm.

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Published Online: 2005-06-01
Published in Print: 2003-02-20

Copyright © 2003 by Walter de Gruyter GmbH & Co. KG

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