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Concurrent estimation of the kinetics of adhesion and ingestion of Staphylococcus aureus by human polymorphonuclear
Abstract:
Direct recording of the kinetics of early phagocytic events, recognition or adhesion and ingestion, may better characterize some forms of polymorphonuclear leukocyte (PMN) dysfunction. This report describes a method and criteria to discriminate concurrently between adhesion and ingestion of Staphylococcus aureus by human PMNs at the level of the light microscope. The criteria were confirmed by several lines of direct evidence: low temperature and cytochalasin b treatment of PMNs; lysostaphin digestion of target Staphylococcus aureus after PMN incubation; and differential ingestibility of colony types I and III N. gonorrheae. Concurrent determinations of the initial kinetics of adhesion and ingestion of bacteria by PMNs demonstrated generalized first order kinetics, sensitive to bacterial challenge ratio and total particle density. Most importantly, the method may be applied to determine if phagocytically defective PMNs actually fail to recognize opsonized bacteria.
Insights
This study presents a new light microscope method to distinguish between polymorphonuclear leukocyte (PMN) adhesion and ingestion of Staphylococcus aureus. This technique aids in identifying PMN dysfunction by assessing bacterial recognition.
Area of Science:
- Immunology
- Cell Biology
- Microbiology
Background:
- Polymorphonuclear leukocytes (PMNs) are crucial for innate immunity.
- Characterizing PMN dysfunction is essential for understanding immune deficiencies.
- Early phagocytic events like adhesion and ingestion are key indicators of PMN function.
Purpose of the Study:
- To develop and validate a light microscopy method for simultaneously assessing PMN adhesion and ingestion of Staphylococcus aureus.
- To establish criteria for discriminating between these two early phagocytic events.
- To apply this method for evaluating phagocytic defects in PMNs, specifically their ability to recognize opsonized bacteria.
Main Methods:
- Utilizing light microscopy to observe human PMNs interacting with Staphylococcus aureus.
- Employing criteria confirmed by low temperature, cytochalasin B treatment, lysostaphin digestion of bacteria, and differential ingestion of Neisseria gonorrhoeae colony types.
- Analyzing the kinetics of adhesion and ingestion under varying bacterial challenge ratios and particle densities.
Main Results:
- A reliable method was established to concurrently measure Staphylococcus aureus adhesion and ingestion by human PMNs.
- The kinetics of these early phagocytic events followed generalized first-order kinetics.
- The process was found to be sensitive to the bacterial challenge ratio and total particle density.
Conclusions:
- The developed light microscopy method effectively differentiates between PMN adhesion and ingestion of Staphylococcus aureus.
- This technique provides a valuable tool for investigating PMN dysfunction, particularly in assessing the recognition of opsonized bacteria.
- The kinetic analysis offers insights into the quantitative aspects of phagocytosis and its regulation.