Immunocytochemical labeling of Purkinje neurons. Primary cultures of cerebellar neurons and glia were inoculated with the viral vector after 10 days in vitro. The cells were fixed 24 h after inoculation and processed for calbindin immunocytochemistry with a Texas Red labeled secondary antibody. The digital images are inverted so that fluorescence is shown as black on a white background.

(A) Three Purkinje neurons are shown using Texas red optics to indicate the presence of calbindin immunoreactivity. The white arrow indicates two separate neurons.

(B) This image was obtained with FITC optics in order to visualize eGFP. The arrow indicates two neurons that are nearly superimposed. The upper neuron displays strong fluorescence, whereas the lower neuron has a lesser degree of eGFP expression. The Purkinje neuron identified by the black arrow in panel A was not transduced by the viral vector and is not visible in panel B. There are numerous eGFP-expressing glial cells in the background (arrowhead indicates an example).

(C) Calbindin-stained Purkinje cells in an age-matched culture not treated with the viral vector are shown for comparison. Treatment with the viral vector as shown in A and B does not change the morphological features of Purkinje cells.