Clone 13 tropism in the brain parenchyma during persistence. The localization of clone 13 in the brain parenchyma was examined at various time points post-infection by two-color confocal microscopy. During the first 60 days the virus (green) was found primarily in GFAP+ astrocytes (red). Representative low (first row) and high (second row) magnification images are shown for a mouse (n = 3 mice per group) at day 31 p.i. The third row shows a whole brain reconstruction from a mouse (n = 3 mice per group) at day 150 and an enlarged panel of the olfactory bulb. Virus is shown in green and cell nuclei in blue. In the late phase of persistence (day 150), the virus (green) was found primarily in NeuN+ olfactory bulb neurons (red). Low and high magnification examples are shown in the fourth and fifth rows, respectively.