Activation of antiviral CD8 T resident memory cells induces BBB disruption and promotes a shift from active to passive anxiety-like behavior 4340

Description Blood-brain barrier (BBB) disruption is a putative mechanism of neurodegeneration, neuropsychiatric disorders, and long covid. Our laboratory was the first to demonstrate antigen-specific CD8 T cells induce BBB disruption. We now introduce a novel neurologic disease model in which CD8 T resident memory (TRM) cells induce BBB disruption via administration of cognate antigen, long after neurotropic virus is cleared. C57BL/6 mice intracranially infected with Theiler’s murine encephalomyelitis virus (TMEV) clear virus within 21 days. At 2 months post infection, mice received intravenous injection of viral peptide VP2(121-130) for which the largest population of CD8 TRM have T cell receptor specificity for, resulting in BBB permeability detectable by gadolinium enhanced T1 weighted MRI. A second round of BBB disruption was then initiated with VP2 peptide at 4 months post infection. One month after this second induction of BBB disruption, mice underwent behavioral assessments and whole brain flow cytometric analysis. In these mice, we found a significant inverse correlation of BBB breakdown with a shift from active to passive anxiety-like behavior to contextual fear memory compared to mock peptide controls. This shift in anxiety correlated with virus antigen specific CD8 TRM, myeloid, and NK cells. These results demonstrate memory antiviral CD8 T cells can induce BBB disruption, long after virus is cleared, a process that contributes to a shift in anxiety-like behaviors Funding Sources RO1 NS103212, R01 NS122174 Topic Categories Neuroimmunology (NEUR)