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Organophosphorus pesticides induce apoptosis in human NK cells

Qing Li1, Maiko Kobayashi, Tomoyuki Kawada

  • 1Department of Hygiene and Public Health, Nippon Medical School, 1-1-5 Sendagi, Tokyo, Japan. qing-li@nms.ac.jp

Toxicology
|August 8, 2007
PubMed

Insights

Organophosphorus pesticides (OPs) induce apoptosis, or programmed cell death, in natural killer (NK) cells. This finding suggests OPs may impair immune function by triggering NK cell death.

Area of Science:

  • Immunotoxicology
  • Cell Biology
  • Pesticide Toxicology

Background:

  • Organophosphorus pesticides (OPs) are known to inhibit natural killer (NK) cell activity.
  • The precise mechanisms underlying OP-induced NK cell dysfunction require further elucidation.

Purpose of the Study:

  • To investigate whether organophosphorus pesticides (OPs) induce apoptosis in human NK cell lines.
  • To explore the role of caspase-3 activation in OP-induced NK cell apoptosis.

Main Methods:

  • Human NK cell lines (NK-92CI and NK-92MI) were treated with dichlorvos (DDVP) or chlorpyrifos (CP) in vitro.
  • Apoptosis was assessed using FITC-Annexin V staining.
  • Intracellular active caspase-3 levels were analyzed by flow cytometry; caspase-3 inhibition was also tested.

Main Results:

  • Both DDVP and CP significantly induced apoptosis in NK-92CI and NK-92MI cells in a dose- and time-dependent manner.
  • DDVP treatment increased intracellular active caspase-3, and a caspase-3 inhibitor partially blocked DDVP-induced apoptosis.
  • CP exhibited a faster but weaker apoptotic effect at high doses compared to DDVP, while DDVP showed a slower but stronger effect at low doses. NK-92CI cells were more sensitive to OPs than NK-92MI cells.

Conclusions:

  • Organophosphorus pesticides (OPs) can induce apoptosis in human NK cells, at least partially through caspase-3 activation.
  • OP-induced NK cell apoptosis may contribute to the observed inhibition of NK cell activity.
  • Differential sensitivity of NK cell lines to OPs highlights the complexity of pesticide immunotoxicity.

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