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Polymorphonuclear leukocyte kinetics in experimentally induced keratitis
Abstract:
The movement of polymorphonuclear leukocytes (PMNLs) into inflamed corneas was studied using a quantitative technique to measure PMNL chemotaxis in vivo. Our studies suggested that, in this model, most PMNLs enter the cornea through limbal vessels. A variety of bacterial agents, including viable bacteria, killed bacteria, culture filtrates, and endotoxin, were found to induce a significant corneal inflammatory response. Of the agents tested, viable Pseudomonas aeruginosa produced greatest inflammation. Host factors (serum, PMNLs) also induced movement of PMNLs into corneas, but only after preincubation with activating agents. Normal serum, resting PMNLs, and PMNL lysates derived from resting cells did not promote PMNL corneal ingress. These studies provide further insight into the movement of PMNLs into the inflamed cornea and information that may be of use in developing techniques to inhibit the corneal inflammatory response.
Insights
Polymorphonuclear leukocytes (PMNLs) migrate into inflamed corneas primarily via limbal vessels. Bacterial agents, especially Pseudomonas aeruginosa, trigger significant corneal inflammation, influencing PMNL infiltration.
Area of Science:
- Ophthalmology
- Immunology
- Microbiology
Background:
- Corneal inflammation involves the infiltration of polymorphonuclear leukocytes (PMNLs).
- Understanding the mechanisms of PMNL migration is crucial for managing ocular inflammatory diseases.
Purpose of the Study:
- To quantitatively assess PMNL chemotaxis in vivo within inflamed corneas.
- To identify bacterial and host factors influencing PMNL corneal entry.
Main Methods:
- Utilized a quantitative technique to measure PMNL chemotaxis in an in vivo corneal inflammation model.
- Administered various bacterial agents (viable, killed, filtrates, endotoxin) and host factors (serum, PMNLs) to induce and study inflammatory responses.
Main Results:
- Most PMNLs entered the inflamed cornea through limbal vessels.
- Viable Pseudomonas aeruginosa induced the most significant corneal inflammatory response.
- Host factors required pre-activation with specific agents to promote PMNL corneal ingress; resting components did not.
Conclusions:
- Bacterial agents are potent inducers of PMNL corneal infiltration.
- Host factors play a role in PMNL migration but require specific activation.
- Findings offer insights for developing strategies to inhibit corneal inflammatory responses.