Chemotactic factor-specific desensitization of skin to infiltration by polymorphonuclear leukocytes
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Abstract:
The accumulation of polymorphonuclear leukocytes (PMNs) was measured in rabbits following single or repeated injections into skin sites of the inflammatory agents, zymosan-activated plasma and formylmethionyl-leucyl-phenylalanine. Fewer cells entered lesions restimulated with the same agent during the subsequent inflammatory response than simultaneously entered skin sites stimulated for the first time. Decreased reactivity of a restimulated site was specific to the initiating stimulus, developed within 2 to 4 h of initial stimulation and persisted for at least 8 h. The results indicate that PMN accumulation in acute inflammatory lesions is regulated locally by a chemotactic factor-specific mechanism which differs from PMN deactivation and concentration gradient mechanisms currently thought to regulate PMN migration in vivo.
Insights
Inflammation response in rabbits shows that previously stimulated skin sites attract fewer polymorphonuclear leukocytes (PMNs). This localized, stimulus-specific decrease in PMN accumulation suggests a novel regulatory mechanism in acute inflammation.
Area of Science:
- Immunology
- Inflammation Biology
Background:
- Polymorphonuclear leukocytes (PMNs) are crucial for acute inflammatory responses.
- Current understanding suggests PMN migration is regulated by deactivation and concentration gradients.
Purpose of the Study:
- To investigate the local regulation of PMN accumulation in response to inflammatory stimuli.
- To determine if prior stimulation affects subsequent inflammatory cell recruitment.
Main Methods:
- Rabbits received single or repeated injections of inflammatory agents (zymosan-activated plasma, formylmethionyl-leucyl-phenylalanine) into skin sites.
- PMN accumulation was quantified in both initially stimulated and previously stimulated (restimulated) sites.
Main Results:
- Restimulated skin sites showed significantly reduced PMN influx compared to newly stimulated sites.
- This decreased reactivity was specific to the initial inflammatory agent.
- The effect developed within 2-4 hours and persisted for at least 8 hours.
Conclusions:
- PMN accumulation in acute inflammatory lesions is regulated by a local, chemotactic factor-specific mechanism.
- This mechanism differs from established models of PMN deactivation and concentration gradients.
- Findings suggest a novel pathway for controlling inflammatory cell migration in vivo.