Activation of an astrocyte stress response in the brain accompanies peptide-induced fatal syndrome as determined by quantifiable glial fibrillary acidic protein Western blot analysis. C57BL/6 and 129 SvIm strain animals were infected for 7 days intracranially with Theiler's murine encephalomyelitis virus prior to systemic treatment with VP2121-130 peptide to induce peptide-induced fatal syndrome. Twenty-four hours after peptide treatment the right hemispheres of mice were homogenized and analyzed for glial fibrillary acidic protein (GFAP) levels. Shown are protein levels and normalization of GFAP to glyceraldehyde 3-phosphate dehydrogenase as a loading control. Asterisks denote statistical significance (P < 0.05) between treatment groups. Each group consisted of six mice. One VP2121-130 peptide-treated C57BL/6 mouse had to be killed and was removed from the study.