Impact of polysialylated CD56 on natural killer cell cytotoxicity.
BACKGROUND
Siglec-7, a sialic acid binding inhibitory receptor expressed by NK cells is masked in vivo by a so far unknown ligand. It shows a strong binding prevalence for alpha-2,8-linked disialic acids in vitro.


RESULTS
Here we describe the expression of PSA-NCAM (alpha-2,8-linked polysialic acid modified NCAM) on functional adult peripheral blood natural killer cells and examine its possible role in masking Siglec-7. Unmasking of Siglec-7 using Clostridium perfringens neuraminidase massively reduces NK cell cytotoxicity. By contrast a specific removal of PSA using Endo-NF does not lead to a reduction of NK cell cytotoxicity.


CONCLUSIONS
The results presented here therefore indicate that PSA-NCAM is not involved in masking Siglec-7.
Miltenyi Biotec GmbH, Bergisch Gladbach, Germany.
Jeannette M
JM
Moebius
Darius
D
Widera
Juergen
J
Schmitz
Christian
C
Kaltschmidt
Christoph
C
Piechaczek
D015214:Antigens, Differentiation, Myelomonocytic / Q000378:metabolism; D019002:CD56 Antigen / Q000276:immunology* / Q000378:metabolism*; D002460:Cell Line; D002469:Cell Separation; D003602:Cytotoxicity, Immunologic / Q000276:immunology*; D006801:Humans; D007694:Killer Cells, Natural / Q000201:enzymology / Q000276:immunology*; D037102:Lectins / Q000378:metabolism; D009439:Neuraminidase / Q000378:metabolism; D012794:Sialic Acids / Q000378:metabolism*; D012799:Sialyltransferases / Q000378:metabolism
D015214:Antigens, Differentiation, Myelomonocytic; D019002:CD56 Antigen; D037102:Lectins; C402206:SIGLEC7 protein, human; D012794:Sialic Acids; C021319:polysialic acid; D012799:Sialyltransferases; D009439:Neuraminidase