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Published on: March 17, 2014
Control of Pseudomonas aeruginosa skin infections in mice is mast cell-dependent
Frank Siebenhaar1, Wolfgang Syska, Karsten Weller
1Department of Dermatology and Allergy, Allergie-Centrum-Charité, Charité-Universitätsmedizin Berlin, Charitéplatz 1, D-10117 Berlin, Germany.
Abstract:
Mast cells (MCs) have recently been shown to be essential for the elicitation of efficient immune responses in murine sepsis. To explore whether MCs also contribute to the control of bacterial skin infections, we studied skin lesions induced by Pseudomonas aeruginosa (PA) in genetically MC-deficient Kit(W)/Kit(W-v) mice, normal Kit(+/+) mice, and MC-reconstituted Kit(W)/Kit(W-v) mice. PA injections resulted in strikingly (>2-fold) larger skin lesions in Kit(W)/Kit(W-v) mice than in Kit(+/+) mice, which exhibited pronounced MC degranulation at infection sites. In addition, neutrophil recruitment following PA injections and bacterial clearance from sites of infection was significantly impaired in Kit(W)/Kit(W-v) mice compared with Kit(+/+) mice. Notably, the adoptive transfer of MCs to the skin of Kit(W)/Kit(W-v) mice before PA infection resulted in normal neutrophil accumulation as well as skin lesions comparable with those in Kit(+/+) mice in both bacterial burden and size. These findings demonstrate for the first time that activated MCs are crucial for the induction of protective innate immune responses to bacterial skin infections.
Insights
Mast cells are vital for controlling bacterial skin infections. In mice lacking mast cells, Pseudomonas aeruginosa infections caused larger lesions and impaired bacterial clearance, highlighting mast cells' protective role.
Area of Science:
- Immunology
- Dermatology
- Microbiology
Background:
- Mast cells (MCs) are known to be essential for immune responses in murine sepsis.
- Their role in bacterial skin infections, however, remains largely unexplored.
Purpose of the Study:
- To investigate the contribution of mast cells to the control of Pseudomonas aeruginosa (PA) skin infections.
- To determine if mast cells are crucial for protective innate immune responses against bacterial skin pathogens.
Main Methods:
- Studied skin lesions induced by PA in genetically MC-deficient Kit(W)/Kit(W-v) mice, normal Kit(+/+) mice, and MC-reconstituted Kit(W)/Kit(W-v) mice.
- Assessed lesion size, neutrophil recruitment, and bacterial clearance.
- Utilized adoptive transfer of MCs to MC-deficient mice.
Main Results:
- MC-deficient mice exhibited significantly larger skin lesions (>2-fold) compared to normal mice.
- Neutrophil recruitment and bacterial clearance were impaired in MC-deficient mice.
- Adoptive transfer of MCs restored normal neutrophil accumulation and lesion control in deficient mice.
Conclusions:
- Activated mast cells are crucial for inducing protective innate immune responses against bacterial skin infections.
- Mast cells play a significant role in controlling Pseudomonas aeruginosa skin infections by facilitating neutrophil recruitment and bacterial clearance.
