Long term immunologic consequences of experimental stroke and mucosal tolerance

Area of Science:

• Neuroimmunology
• Stroke research
• Autoimmunity

Background:

• Middle cerebral artery occlusion (MCAO) triggers inflammation and autoimmune responses to myelin basic protein (MBP).
• Pre-stroke immunologic tolerance induction to brain antigens improves early functional outcomes.
• Long-term immune consequences of experimental stroke and tolerance induction require investigation.

Purpose of the Study:

• To investigate the long-term immunologic effects of experimental stroke.
• To determine the consequences of inducing mucosal tolerance to brain antigens prior to stroke.

Main Methods:

• Lewis rats received intranasal tolerance induction to MBP or ovalbumin (OVA) before MCAO and LPS administration.
• Neurological outcomes were assessed post-MCAO, with animals sacrificed at 3 months.
• Immune responses to MBP (ELISPOT) and brain inflammation (immunocytochemistry) were analyzed.

Main Results:

• A pro-inflammatory (TH1) response to MBP correlated with worse outcomes, while a regulatory (TREG) response correlated with better outcomes.
• TREG response in spleen was linked to reduced brain inflammation and increased FoxP3+ cells.
• Pre-stroke tolerance induction to MBP showed a trend toward a TH1 response by 3 months post-MCAO.

Conclusions:

• Immunological tolerance induction to MBP improves stroke outcomes.
• Mucosal antigen administration for tolerance induction may inadvertently trigger detrimental autoimmunity.
• Further research is needed to balance therapeutic tolerance with autoimmune risks.