Experimental ischemic stroke induces long-term T cell activation in the brain

Area of Science:

• Neuroimmunology
• Stroke Research
• Immunology

Background:

• Innate and adaptive immune cells infiltrate the brain post-ischemic stroke.
• T cell invasion in the ischemic brain persists long-term in patients.
• The function and characteristics of brain-invading T cells post-stroke remain unclear.

Purpose of the Study:

• To investigate the function and phenotype of brain-invading T cells during acute and chronic phases after experimental ischemic stroke.
• To characterize the immune response in the peri-infarct area following stroke.

Main Methods:

• Experimental ischemic stroke induced by transient middle cerebral artery occlusion.
• Analysis of CD4+ and CD8+ T cell presence and phenotype in the peri-infarct area.
• Assessment of T cell activation markers, cytokine expression, and transcriptional factors.

Main Results:

• Significant increase in CD4+ and CD8+ T cells in the peri-infarct zone up to one month post-stroke.
• Brain-invading T cells exhibited close interaction with active astrocytes.
• Progressive proinflammatory phenotype observed, with increased expression of activation markers (CD44, CD25), cytokines (INF-γ, IL-17, IL-10, TNF-α), and transcription factors (T-bet, RORc).

Conclusions:

• Prolonged activation of CD4+ and CD8+ T cells occurs in the brain after ischemic stroke.
• These activated T cells may play a role in the neural repair processes following stroke.