FIG.3.

Quantitation of neuronal apoptosis induced by HIV-1-infected MDM. NT2.N-astrocyte cultures were exposed to HIV-1-infected MDM supernatants or glutamate (Glut) (1 mM) and subjected to TUNEL assay as described in Materials and Methods. After 48 h, TUNEL-positive neurons were counted in five fields per coverslip by a blinded examiner. Each isolate was tested in two to three independent experiments, with two to three coverslips examined within each experiment. Results were expressed as the average percentage of TUNEL-positive neurons for all experiments ± standard error. (A) Phase-contrast photographs of TUNEL images from representative fields of neuronal-astrocyte cultures after exposure. Arrows indicate representative TUNEL-positive neurons. Magnification, ×200. (B) Average total percent neuronal apoptosis for all experiments. Total experiments examined were as follows: mock, n = 3; 89.6, n = 3; tybe, n = 3; jago, n = 3; doge, n = 2; glutamate, n = 2. Comparisons of means were made by Student's t test.