Related Experiment Video
Updated: Sep 26, 2026
Neutrophil Lifespan Extension with CLON-G and an In Vitro Spontaneous Death Assay
Published on: May 12, 2023
Anaplasma phagocytophilum reduces neutrophil apoptosis in vivo
Helena Scaife1, Zerai Woldehiwet, C Anthony Hart
1School of Biological Sciences, Life Sciences Building, University of Liverpool, Liverpool L69 3BX, United Kingdom.
Abstract:
Ovine neutrophils spontaneously underwent apoptosis during culture in vitro, as assessed by morphological changes and exposure of annexin V binding sites on their cell surfaces. The addition of conditioned medium from concanavalin A-treated ovine peripheral blood mononuclear cells (PBMC) could partially protect against this progression into apoptosis, but dexamethasone and sodium butyrate could not. Actinomycin D accelerated the rate at which ovine neutrophils underwent apoptosis. Neutrophils isolated from sheep experimentally infected with Anaplasma phagocytophilum showed significantly delayed apoptosis during culture ex vivo, and the addition of conditioned medium from PBMC to these cells could not delay apoptosis above the protective effects observed after in vivo infection. The ability of neutrophils from A. phagocytophilum-infected sheep to activate a respiratory burst was increased compared to the activity measured in neutrophils from uninfected sheep, but chemotaxis was decreased in neutrophils from infected sheep. These data are the first demonstration that in vivo infection with A. phagocytophilum results in changes in rates of apoptosis of infected immune cells. This may help explain how these bacteria replicate in these normally short-lived cells.
Insights
Sheep neutrophils undergo programmed cell death (apoptosis) naturally. Infection with Anaplasma phagocytophilum delays this process, potentially aiding bacterial survival in these immune cells.
Area of Science:
- Immunology
- Cell Biology
- Veterinary Medicine
Background:
- Ovine neutrophils undergo spontaneous apoptosis in vitro.
- Apoptosis is a programmed cell death process crucial for immune regulation.
- Anaplasma phagocytophilum is an intracellular bacterium that infects neutrophils.
Purpose of the Study:
- To investigate the effect of Anaplasma phagocytophilum infection on ovine neutrophil apoptosis.
- To explore the mechanisms influencing neutrophil apoptosis during infection.
- To understand how altered apoptosis impacts bacterial survival.
Main Methods:
- Ovine neutrophils were cultured in vitro.
- Apoptosis was assessed via morphological changes and annexin V binding.
- Conditioned media from peripheral blood mononuclear cells (PBMC), dexamethasone, sodium butyrate, and actinomycin D were used.
- Neutrophil function (respiratory burst, chemotaxis) was measured in infected and uninfected sheep.
Main Results:
- Ovine neutrophils spontaneously underwent apoptosis in vitro.
- Conditioned PBMC medium partially protected against apoptosis; dexamethasone and sodium butyrate did not.
- Actinomycin D accelerated neutrophil apoptosis.
- Neutrophils from Anaplasma phagocytophilum-infected sheep exhibited delayed apoptosis ex vivo.
- Infection increased neutrophil respiratory burst activity but decreased chemotaxis.
Conclusions:
- In vivo Anaplasma phagocytophilum infection alters ovine neutrophil apoptosis rates.
- Delayed apoptosis in infected neutrophils may facilitate bacterial replication.
- These findings provide insights into the pathogenesis of Anaplasma phagocytophilum infections.
More Related Videos
10:05Development and Identification of a Novel Subpopulation of Human Neutrophil-derived Giant Phagocytes In Vitro
Published on: January 25, 2017
09:18Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
Published on: December 27, 2016
