Microglia activation accompanied by prominent astrogliosis in double immune-challenged non-transgenic mice. Immunoperoxidase staining of brain sections from 18-month-old NP (NaCl at gestation day (GD)17, PolyI:C at 15 months) and PP (polyriboinosinic-polyribocytidilic acid (PolyI:C) at GD17, PolyI:C at 15 months) mice. Increase in (A-D) CD68 and (E-H) glial fibrillary acidic protein (GFAP) immunoreactivity (IR) in the PP hippocampus. (D) Note the strong hypertrophy of CD68-positive microglia in PP versus NP subjects, indicative of their activated state. Quantitative analysis of hippocampal (I) anti-CD68 and (J) GFAP IR representing total area and mean size of activated microglia and astrocytes, respectively. Values are given as mean ± SEM, n = 5 per treatment. *P < 0.05; statistical significance based on Mann–Whitney U test. Scale bars: (A,E) = 500 μm; (C) = 20 μm, (G) = 50 μm.