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Updated: Jul 27, 2026

Direct Observation of Phagocytosis and NET-formation by Neutrophils in Infected Lungs using 2-photon Microscopy
08:50

Direct Observation of Phagocytosis and NET-formation by Neutrophils in Infected Lungs using 2-photon Microscopy

Published on: June 2, 2011

Neutrophil phagocytosis during endotoxin-induced lung injury

J Griswold1, R V Maier

  • 1Department of Surgery, University of Washington, Seattle.

The Journal of Surgical Research
|April 1, 1988
PubMed
Abstract

Insights

Neutrophil phagocytosis is impaired in acute lung injury (ALI), potentially increasing sepsis risk. Alveolar neutrophils in endotoxin-induced ALI show reduced adherence and yeast uptake, contributing to impaired bacterial clearance.

Area of Science:

  • Immunology
  • Pulmonary Medicine
  • Cell Biology

Background:

  • Neutrophil (PMN) dysfunction, particularly reduced phagocytosis, is implicated in the heightened susceptibility to pulmonary sepsis observed in patients with acute respiratory distress syndrome (ARDS).
  • Understanding the specific mechanisms of PMN impairment in ARDS is crucial for developing targeted therapies to improve outcomes.

Purpose of the Study:

  • To investigate alterations in neutrophil phagocytosis and adherence in a rat model of acute lung injury induced by endotoxin infusion.
  • To compare the functional capacity of circulating neutrophils versus neutrophils isolated from the alveolar space in rats with endotoxin-induced lung injury.

Main Methods:

  • Neutrophils were isolated from the circulation and bronchoalveolar lavage (BAL) fluid of rats subjected to 72 hours of endotoxin (LPS-Rx) infusion.
  • Neutrophil adherence was assessed using a nylon wool column, and phagocytosis was measured by incubating neutrophils with opsonized, fluorescently tagged yeast particles.
  • Flow cytometry was used to quantify the percentage of neutrophils ingesting yeast and the number of yeast particles per neutrophil.

Main Results:

  • Neutrophil adherence to nylon wool was significantly reduced in BAL neutrophils (20%) compared to circulating neutrophils (77%) from LPS-Rx rats and control rats (65%).
  • Phagocytosis of yeast was significantly decreased in BAL neutrophils, with fewer neutrophils ingesting yeast (78.7%) and a lower number of yeast particles per 100 neutrophils (170) compared to control (95.4% and 270, respectively).
  • Circulating neutrophils from LPS-Rx rats showed phagocytic capacity comparable to control neutrophils.

Conclusions:

  • Intra-alveolar neutrophils (BAL PMNs) exhibit diminished adherence and significantly reduced phagocytic capacity for yeast in a rat model of acute lung injury.
  • These functional deficits in alveolar neutrophils may contribute to the impaired bacterial clearance and increased risk of pulmonary sepsis associated with ARDS.
  • The findings highlight a potential mechanism underlying the increased incidence of secondary infections in critically ill patients with lung injury.

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