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Influence of fluid-phase chemoattractants on polymorphonuclear leukocyte chemotaxic responsiveness to a surface-bound
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. Addition of a complement source to yeast particles able to activate the complement system resulted in a chemotactic response even when fluid-phase attractants were removed prior to the measurement of PMNL chemotaxis, indicating that surface-bound attractants guided the PMNLs to the yeast particles. The presence of high concentrations of fluid-phase chemoattractants resulted in a reduced PMNL chemotactic response to the surface-bound gradient. From comparisons between the yeast-slide system and the locomotion-under-agarose assay, it could be concluded that PMNL chemotaxis in response to a surface-bound gradient is less influenced by factor-specific deactivation than the response to a fluid-phase attractant. The PMNL chemotactic response is reduced to both surface-bound and fluid-phase gradients as a result of a non-factor-specific deactivation.
Insights
Polymorphonuclear leukocytes (PMNLs) use surface-bound signals for directed movement, even without fluid attractants. High fluid attractant levels and non-specific deactivation can impair this crucial immune cell chemotaxis.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- Polymorphonuclear leukocytes (PMNLs) are critical immune cells involved in pathogen clearance.
- Chemotaxis, the directed movement of cells in response to chemical gradients, is essential for PMNL function.
- Understanding how PMNLs respond to different types of chemoattractants is vital for immune response.
Purpose of the Study:
- To investigate PMNL chemotaxis towards surface-bound chemoattractants.
- To compare PMNL responses to surface-bound versus fluid-phase attractants.
- To elucidate the mechanisms of PMNL deactivation in response to chemoattractants.
Main Methods:
- Utilized a yeast-slide system to present fixed yeast particles as a surface-bound chemoattractant source.
- Quantified PMNL locomotion by counting yeast particles associated with individual PMNLs.
- Compared responses in the presence and absence of fluid-phase chemoattractants and under varying deactivation conditions.
Main Results:
- PMNLs exhibited chemotaxis towards surface-bound attractants on yeast particles, even without fluid-phase signals.
- High concentrations of fluid-phase chemoattractants reduced the chemotactic response to surface-bound gradients.
- PMNL chemotaxis to surface-bound gradients was less affected by factor-specific deactivation than responses to fluid-phase attractants.
Conclusions:
- Surface-bound chemoattractant gradients effectively guide PMNL migration.
- Non-specific deactivation significantly impairs PMNL chemotaxis to both surface-bound and fluid-phase gradients.
- PMNLs exhibit distinct deactivation sensitivities depending on the chemoattractant presentation.