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The role of regulatory T cells in the resistance of CCR4 knockout mice during severe sepsis
Critical Care volume 11, Article number: P2 (2007)
Studies reveal that regulatory T (Treg) cells control immune responses; therefore these responses must be controlled to enable effective protection against infections and cancer. CCR4 knockout (CCR4-/-) mice are more resistant to lipopolysaccharide shock. So, our aim is to study the mechanisms involved in the resistance of CCR4-/- mice subjected to severe sepsis by cecal ligation and puncture (CLP) and how Treg cells modulate this effect.
C57/BL6 mice were subjected to a CLP model, whereby the cecum was partially ligated and punctured nine times with a 21 G needle. Sham-operated mice were used as control. Mice subjected to CLP and sham surgery were treated with antibiotic from 6 hours after surgery until 3 days.
CCR4-/- mice subjected to CLP presented an increase in the survival rate (78%) compared with wild-type mice (17%), and presented a marked improvement in the innate response concerning neutrophil migration to the peritoneum and lung, bacterial load and cytokine levels compared with wild-type mice. Besides, Treg cells from CCR4-/- CLP mice did not inhibit proliferation of T effector cells as observed for Treg cells from wild CLP mice, at a proportional ratio of T effector: Treg cells. Interesting, Treg cells from CCR4-/- CLP mice inhibit 30% of neutrophil migration to bronchoalveolar lavage when co-injected with fungal challenge as secondary infection in sham recipient mice, while the cells Treg from wild CLP mice inhibit 80%, much more than expected.
These results suggest that Treg cells from CCR4-/- mice did not present a suppressive response and this could be an important factor in their survival. These results are strong evidence for the role of Treg cells in immunosuppression following severe sepsis.
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Molinaro, R., de França, A.M., Alves-Filho, J. et al. The role of regulatory T cells in the resistance of CCR4 knockout mice during severe sepsis. Crit Care 11, P2 (2007). https://doi.org/10.1186/cc5981
- Severe Sepsis
- Treg Cell
- Bronchoalveolar Lavage
- Bacterial Load
- Effective Protection