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Updated: Jul 13, 2026

Measurement of Natural Killer Cell-Mediated Cytotoxicity and Migration in the Context of Hepatic Tumor Cells
Published on: February 22, 2020
Impact of polysialylated CD56 on natural killer cell cytotoxicity
Jeannette M Moebius1, Darius Widera, Juergen Schmitz
1Miltenyi Biotec GmbH, Bergisch Gladbach, Germany.
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.
Conclusion:
The results presented here therefore indicate that PSA-NCAM is not involved in masking Siglec-7.
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