Chemotaxis of polymorphonuclear leukocytes in response to surface-bound complement-derived chemoattractants generated in situ
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Abstract:
Polymorphonuclear leukocytes (PMNLs) were allowed to migrate on slides with fixed yeast particles dotted about on the surface. Locomotion was quantified by counting the number of yeast particles in association with a PMNL. Yeast particles that differed in their ability to consume hemolytic complement differed also in their ability to generate chemoattractants. Addition of a complement source to yeast particles able to activate the complement system resulted in a chemotactic response, as well as when fluid-phase attractants were removed prior to the measurement of PMNL chemotaxis, indicating that the chemoattractants generated were absorbed to the surface. Using an immunofluorescence technique, it was found that complement factor 5 coated a circular area around each yeast particle, provided that the particles were able to activate the complement system.
Insights
Polymorphonuclear leukocytes (PMNLs) migration is influenced by yeast particles. Complement activation on yeast surfaces generates chemoattractants, enhancing PMNL chemotaxis and indicating surface-bound attractants.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Polymorphonuclear leukocytes (PMNLs) are crucial immune cells involved in inflammatory responses.
- Chemoattractants play a vital role in directing leukocyte migration to sites of infection or injury.
- The interaction between yeast particles and complement system components can influence immune cell behavior.
Purpose of the Study:
- To investigate the role of complement activation on yeast particles in generating chemoattractants for PMNLs.
- To determine if chemoattractants generated by yeast particles are surface-absorbed, influencing PMNL locomotion.
- To visualize the deposition of complement factors on yeast particles during PMNL chemotaxis.
Main Methods:
- PMNLs were induced to migrate on slides containing fixed yeast particles.
- Locomotion was quantified by counting yeast particles associated with PMNLs.
- Immunofluorescence techniques were employed to detect complement factor deposition.
Main Results:
- Yeast particles varied in their ability to activate the complement system and generate chemoattractants.
- Addition of complement source to activatable yeast particles induced PMNL chemotaxis, even without fluid-phase attractants.
- Complement factor 5 (C5) was observed to coat yeast particles that activated the complement system.
Conclusions:
- Chemoattractants generated by complement activation on yeast particles are surface-absorbed, directing PMNL migration.
- The ability of yeast particles to activate the complement system directly correlates with their capacity to attract PMNLs.
- Complement factor 5 deposition around yeast particles is a key indicator of complement system activation and subsequent PMNL chemotaxis.