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Updated: Nov 18, 2025
The Isolation and Characterization of Low- and Normal- Density Neutrophils from Whole Blood
Published on: February 7, 2025
Identification and characterization of neutrophil heterogeneity in sepsis
1School of Medicine, Jiangsu University, Zhenjiang, 212001, Jiangsu Province, China.
Insights
Sepsis induces neutrophil dysfunction, characterized by impaired chemotaxis and infiltration. A novel subset of immunosuppressive neutrophils expressing PD-L1 was identified, impacting T cell responses.
Area of Science:
- Immunology
- Cell Biology
- Sepsis Pathophysiology
Background:
- Neutrophil immune function in sepsis is known, but their heterogeneity is not well understood.
- Sepsis involves complex immune responses, with neutrophils playing a critical role.
Purpose of the Study:
- To investigate neutrophil heterogeneity and function during sepsis.
- To identify novel neutrophil subsets and their role in sepsis-induced immune dysregulation.
Main Methods:
- A mouse cecal ligation and puncture (CLP) model was used to simulate sepsis.
- In vitro lipopolysaccharide (LPS) stimulation of neutrophils and single-cell RNA sequencing were employed.
- Coculture of PD-L1 knockout neutrophils with wild-type mouse lymphocytes.
Main Results:
- Neutrophils exhibited dysfunction in late-stage sepsis, including inhibited apoptosis, impaired chemotaxis, and tissue infiltration.
- Single-cell RNA sequencing revealed distinct neutrophil subclusters post-LPS stimulation.
- Overexpressed PD-L1 on neutrophils mediated immunosuppression by inhibiting T cell activation and inducing apoptosis.
Conclusions:
- A novel immunosuppressive neutrophil subset, termed 'inhibitory neutrophils', was identified in sepsis.
- These inhibitory neutrophils contribute to sepsis-induced immune suppression through PD-L1 expression.
- Understanding neutrophil heterogeneity is crucial for sepsis management.
Background:
Although the immune function of neutrophils in sepsis has been well described, the heterogeneity of neutrophils remains unclear during the process of sepsis.
Methods:
In this study, we used a mouse CLP model to simulate the clinical scenario of patients with sepsis, neutrophil infiltration, abnormal distribution and dysfunction was analyzed. LPS was used to stimulate neutrophils in vitro to simulate sepsis; single-cell gene sequencing technology was used to explore the immunological typing. To explore the immunological function of immunosuppressive neutrophils, PD-L1 knockout neutrophils were cocultured with lymphocytes from wild-type mice.
Results:
We found that neutrophils presented variant dysfunction at the late stage of sepsis, including inhibition of apoptosis, seriously damaged chemotaxis and extensive infiltration into the tissues. Single-cell RNA sequencing revealed that multiple subclusters of neutrophils were differentiated after LPS stimulation. The two-dimensional spatial distribution analysis showed that Foxp3+ T cells were much closer to Ly-6G than the CD4+ and CD8+ cells, indicating that infiltrated neutrophils may play immunomodulatory effect on surrounding T-regs. Further observations showed that LPS mediates PD-L1 over expression through p38α-MSK1/-MK2 pathway in neutrophils. The subsets of highly expressed PD-L1 exert immunosuppressive effect under direct contact mode, including inhibition of T cell activation and induction of T cell apoptosis and trans-differentiation.
Conclusions:
Taken together, our data identify a previously unknown immunosuppressive subset of neutrophils as inhibitory neutrophil in order to more accurately describe the phenotype and characteristics of these cells in sepsis.
