Expression analysis of the ligands for the Natural Killer cell receptors NKp30 and NKp44.
BACKGROUND
The natural cytotoxicity receptors (NCR) are important to stimulate the activity of Natural Killer (NK) cells against transformed cells. Identification of NCR ligands and their level of expression on normal and neoplastic cells has important implications for the rational design of immunotherapy strategies for cancer.


RESULTS
Here we analyze the expression of NKp30 ligand and NKp44 ligand on 30 transformed or non-transformed cell lines of different origin. We find intracellular and surface expression of these two ligands on almost all cell lines tested. Expression of NKp30 and NKp44 ligands was variable and did not correlate with the origin of the cell line. Expression of NKp30 and NKp44 ligand correlated with NKp30 and NKp44-mediated NK cell lysis of tumor cells, respectively. The surface expression of NKp30 ligand and NKp44 ligand was sensitive to trypsin treatment and was reduced in cells arrested in G(2)/M phase.


CONCLUSIONS
These data demonstrate the ubiquitous expression of the ligands for NKp30 and NKp44 and give an important insight into the regulation of these ligands.
Byrd
Andreina
A
Institute for Immunology, University Heidelberg, Heidelberg, Germany.
Hoffmann
Sabrina C
SC
Jarahian
Mostafa
M
Momburg
Frank
F
Watzl
Carsten
C
D002461:Cell Line, Transformed; D006801:Humans; D007694:Killer Cells, Natural / Q000378:metabolism*; D008024:Ligands; D055629:Natural Cytotoxicity Triggering Receptor 2; D055628:Natural Cytotoxicity Triggering Receptor 3; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*
D008024:Ligands; C112837:NCR2 protein, human; C431710:NCR3 protein, human; D055629:Natural Cytotoxicity Triggering Receptor 2; D055628:Natural Cytotoxicity Triggering Receptor 3; D011971:Receptors, Immunologic