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Ablation of natural killer cell function by soluble cardiotoxin
1Department of Medicinal and Biological Chemistry, University of Toledo, Ohio.
Abstract:
A one-hour preincubation of nonadherent murine spleen cells with a soluble membrane-active cardiotoxin purified from the venom of the Thailand cobra Naja naja siamensis results in the destruction of natural killer (NK) cell activity against YAC-1 target cells in a dose-dependent manner. Prior in vivo induction of interferon production by polyinosinic/polycytidylic acid does not avert the cardiotoxin inhibition of NK function. Loss of complement-mediated lysis of cells capable of binding an NK-1.1 monoclonal antibody suggests that the cardiotoxin directly affects the integrity of the NK cell plasma membrane. Cardiotoxin which has been adsorbed to the surface of polystyrene tissue culture plates retains the ability to lyse splenic T lymphocytes, but loses the ability to interfere with NK activity, as measured either by the release of 51Cr or by the uptake of 3H-thymidine by the target lymphoma cells, suggesting that different parts of the cardiotoxin molecule are responsible for destruction of the two types of lymphocytes.
Insights
Thailand cobra venom cardiotoxin inhibits natural killer (NK) cell activity by damaging their plasma membrane. This effect is dose-dependent and not prevented by interferon induction.
Area of Science:
- Immunology
- Toxicology
- Cell Biology
Background:
- Natural killer (NK) cells are crucial for innate immunity, targeting tumor cells.
- Snake venom cardiotoxins are known for their membrane-disrupting properties.
Purpose of the Study:
- To investigate the effect of Thailand cobra cardiotoxin on NK cell activity.
- To determine the mechanism by which cardiotoxin affects NK cells.
Main Methods:
- Murine spleen cells were preincubated with purified cobra cardiotoxin.
- NK cell activity was measured against YAC-1 target cells using 51Cr release and 3H-thymidine uptake assays.
- Complement-mediated lysis and antibody binding assays were performed.
Main Results:
- Cardiotoxin dose-dependently inhibited NK cell activity against YAC-1 cells.
- Interferon induction did not protect NK cells from cardiotoxin.
- Cardiotoxin appeared to directly damage the NK cell plasma membrane.
- Adsorbing cardiotoxin to plates reduced its effect on NK cells but not T lymphocytes.
Conclusions:
- Cardiotoxin directly impairs NK cell function, likely by disrupting the plasma membrane.
- Different molecular regions of cardiotoxin are responsible for its effects on NK cells and T lymphocytes.