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Natural killer cells lack ecto-5'-nucleotidase
1Department of Infectious Diseases M, Rigshospitalet, University Hospital, Copenhagen, Denmark.
Natural Immunity
|January 1, 1992
Summary
Natural killer (NK) cells lack ecto-5'-nucleotidase (ecto-5'-NUC) activity, making them the sole blood mononuclear cell subset without this enzyme. This finding clarifies the distribution of ecto-5'-NUC in immune cells.
Area of Science:
- Immunology
- Cell Biology
- Biochemistry
Background:
- Ecto-5 '-nucleotidase (ecto-5 '-NUC, CD73) is a plasma membrane enzyme crucial for purine metabolism.
- This enzyme is typically found across various blood mononuclear cell (BMC) subpopulations.
- Its presence is vital for nucleoside transport across the plasma membrane.
Purpose of the Study:
- To investigate the presence and activity of ecto-5 '-NUC in purified natural killer (NK) cells.
- To determine if NK cells, unlike other BMCs, possess ecto-5 '-NUC activity.
Main Methods:
- Purification of NK cells using fluorescence-activated cell sorting (FACS) based on CD16 expression.
- Quantification of ecto-5 '-NUC activity via radioisotope assays.
- Assessment of ecto-5 '-NUC presence at the cellular level using cytochemical assays.
Main Results:
- Purified NK cells exhibited minimal ecto-5 '-NUC activity, below 1 U/10(6) cells by radioisotope assay.
- Cytochemical assays indicated that less than 1% of NK cells displayed ecto-5 '-NUC activity.
- The observed low activity is likely attributable to contaminating non-NK cells.
Conclusions:
- NK cells represent the only known BMC subset devoid of ecto-5 '-NUC activity.
- This finding refines our understanding of ecto-5 '-NUC distribution within the immune system.
- The absence of ecto-5 '-NUC in NK cells may have implications for their function and interactions.