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Updated: Jun 10, 2025
Long Term Chronic Pseudomonas aeruginosa Airway Infection in Mice
Published on: March 17, 2014
Repetitive Acinetobacter baumannii pneumonia induces infection tolerance in mice
Jianqiao Xu1, Wanxue He2, Nan Xiao3
1College of Pulmonary and Critical Care Medicine, 8th Medical Center of Chinese PLA General Hospital (PLA Medical School), Beijing, China.
Abstract:
Some long-term hospitalized patients with lung infections exhibit pathogen tolerance. To investigate whether long-term chronic infection can induce tolerance, we constructed a mouse model of pneumonia in which mice were infected once, twice, or three times with Acinetobacter baumannii. The results revealed that the inflammatory factor levels decreased in the lung lavage fluid and that pathological damage to the lung tissue was alleviated in the mice infected three times. Flow cytometry and transcriptome analysis of mouse lung tissue revealed that the expression of genes related to T cell activation, differentiation, and regulation and the proportion and number of regulatory T cells and immune suppression-related genes, such as Ctla4, Tigit, Slamf8, ICOS, and IDO1, were increased in mice infected three times. These findings show that repeated A. baumannii infections can induce tolerance, which may be mediated by immune suppression involving regulatory T cells.
Insights
Repeated Acinetobacter baumannii lung infections can induce pathogen tolerance. This tolerance may involve immune suppression by regulatory T cells, reducing inflammation and lung damage.
Area of Science:
- Immunology
- Microbiology
- Pathogen-host interactions
Background:
- Long-term hospitalized patients with lung infections can develop pathogen tolerance.
- Chronic infections may lead to the induction of such tolerance.
Purpose of the Study:
- To investigate if repeated Acinetobacter baumannii infections induce pathogen tolerance in a mouse model.
- To explore the immunological mechanisms underlying infection-induced tolerance.
Main Methods:
- A mouse model of pneumonia was established with single, double, or triple Acinetobacter baumannii infections.
- Lung lavage fluid and lung tissue were analyzed for inflammatory factors, pathological damage, and gene expression.
- Flow cytometry and transcriptome analysis were employed to assess immune cell populations and gene expression profiles.
Main Results:
- Mice with triple infections showed decreased inflammatory factor levels and alleviated lung tissue damage.
- Increased expression of genes related to T cell regulation and immune suppression (e.g., Ctla4, Tigit, IDO1) was observed.
- A higher proportion and number of regulatory T cells were identified in mice with repeated infections.
Conclusions:
- Repeated Acinetobacter baumannii infections can induce a state of pathogen tolerance.
- Immune suppression mediated by regulatory T cells appears to be a key mechanism in this induced tolerance.
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