Fig. 2
From: Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases
POWV infection and innate immune response for the neuroinflammatory response. Powassan virus (POWV) directly infects Mφ at early onset causing indirect activation of natural killer (NK), NKT, CD8+ T, and B cells. That infection triggers a protective innate immune response that results in the production of IFNγ, IgM antibodies, and cytolytic proteins including perforin and granzyme B. These factors together cause cytotoxicity of POWV particles (#1). Excessive production of IFNγ turns on the activation of microglial cells. Subsequent release of chemokines attracts inflammatory Th1 cells through the blood–brain barrier (BBB) and causes a demyelinating response in CNS (#2)