Related Experiment Video
Updated: Sep 6, 2026
Time-lapse 3D Imaging of Phagocytosis by Mouse Macrophages
Published on: October 19, 2018
Cinemicrophotographic observations on granule lysis in polymorphonuclear leucocytes during phagocytosis
Abstract:
Phagocytosis of yeast cell walls and of Bacillus megaterium by human, rabbit, and chicken polymorphonuclear leucocytes has been observed by phase contrast microscopy and recorded on motion picture film. In suitably thin preparations intracellular events could be visualized well. Lysis of cytoplasmic granules began early in the course of the ingestion process, rupture occurring only in granules adjacent to the microorganism being engulfed. Formation of a visible vacuole about the ingested particle frequently followed degranulation. Chicken polymorphonuclear leucocytes, with their large phase-dense granules, were particularly suitable subjects for observations on detailed morphologic aspects of granule lysis. Rupture took place rapidly (0.1 second or less); in place of the granule there appeared a clear zone, often with a small phase-dense round structure in its center. Also accompanying granule lysis was an increase in phase density of the adjacent surface of the microorganism. Over the course of the following few seconds the darkening on the organism faded, the dense small body disappeared from view, and the clear zone contracted towards the engulfed particle. The observations are discussed in relation to the hypothesis that fusion takes place between the granule membrane and the invaginated cell membrane overlying the ingested particle, with discharge of granule contents directly into the phagocytic vacuole.
Insights
This study visualizes phagocytosis in polymorphonuclear leukocytes. Granule lysis and vacuole formation occur during the engulfment of microorganisms.
Area of Science:
- Cell Biology
- Immunology
Background:
- Polymorphonuclear leukocytes (PMNs) are crucial immune cells involved in phagocytosis.
- Understanding the intracellular mechanisms of PMN degranulation during phagocytosis is essential for comprehending immune responses.
Purpose of the Study:
- To visualize and describe the dynamic intracellular events during phagocytosis by human, rabbit, and chicken PMNs.
- To investigate the morphologic changes of cytoplasmic granules and the phagocytic vacuole during microorganism engulfment.
Main Methods:
- Phase contrast microscopy was used to observe phagocytosis of yeast cell walls and Bacillus megaterium.
- Motion picture film recording allowed for detailed visualization of intracellular events.
- Observations focused on polymorphonuclear leukocytes from humans, rabbits, and chickens, with a particular emphasis on chicken PMNs due to their distinct granules.
Main Results:
- Cytoplasmic granule lysis initiated early in phagocytosis, with rupture occurring in granules near the ingested particle.
- Degranulation was often followed by the formation of a visible vacuole around the particle.
- Rapid granule rupture (≤0.1 second) resulted in a clear zone and sometimes a central phase-dense structure. The microorganism's surface showed increased phase density, which later faded.
Conclusions:
- The observed events support the hypothesis of granule membrane fusion with the invaginated cell membrane.
- This fusion likely facilitates the direct discharge of granule contents into the phagocytic vacuole.
- Detailed visualization of granule lysis provides insights into the mechanics of phagosome formation and pathogen degradation.
