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Published on: April 2, 2013
Priming effect of pseudomonal leukocidin on chemiluminescence response of rabbit polymorphonuclear leukocytes
1Second Department of Internal Medicine, University of Teikyo, Tokyo, Japan.
Abstract:
To clarify effects of pseudomonal leukocidin (42.5 kd) on chemiluminescence (CL) production of polymorphonuclear leukocytes (PMNs), rabbit PMNs were stimulated by zymosan or phorbol myristate acetate (PMA) after pretreatment with the leukocidin, which by itself stimulated little chemiluminescence response. The extent of CL responses stimulated by zymosan or PMA was respectively 5.3- or 3.5-fold greater in leukocidin (1.5 micrograms/ml)-pretreated PMNs than in non-pretreated ones. The priming effect of the leukocidin was greater than that of G-CSF and related to some steps before NADPH oxidase activation. The increased CL productions might be related to tissue damages caused by pseudomonal infections in vivo.
Insights
Pseudomonal leukocidin primes polymorphonuclear leukocytes (PMNs), significantly enhancing their chemiluminescence response to stimuli. This priming effect, observed in vitro, may contribute to tissue damage during Pseudomonas infections.
Area of Science:
- Immunology
- Microbial Pathogenesis
Background:
- Pseudomonas aeruginosa infections can cause significant tissue damage.
- Leukocidins are toxins produced by bacteria that can damage host immune cells.
- Chemiluminescence (CL) is a measure of reactive oxygen species production by phagocytes, indicating immune cell activation.
Purpose of the Study:
- To investigate the effect of pseudomonal leukocidin on the chemiluminescence (CL) production of rabbit polymorphonuclear leukocytes (PMNs).
- To determine if leukocidin pretreatment enhances PMN responses to common immune stimuli.
Main Methods:
- Rabbit PMNs were pretreated with pseudomonal leukocidin (1.5 µg/ml).
- Pretreated and non-pretreated PMNs were stimulated with zymosan or phorbol myristate acetate (PMA).
- Chemiluminescence (CL) production was measured as an indicator of PMN activation.
Main Results:
- Leukocidin pretreatment significantly increased CL responses to both zymosan (5.3-fold) and PMA (3.5-fold) compared to non-pretreated PMNs.
- The priming effect of leukocidin was more potent than that of G-CSF.
- The mechanism appears to involve steps preceding NADPH oxidase activation.
Conclusions:
- Pseudomonal leukocidin acts as a potent priming agent for PMNs, enhancing their activation.
- This enhanced PMN activity may play a role in the pathogenesis and tissue damage observed in Pseudomonas infections.
- The findings suggest a novel mechanism by which bacterial toxins modulate host immune responses.
