Programmed cell death in HIV-infected macrophages exposed to anti-NGF
Ab. (Left) FACS analysis. Apoptosis was detected
by DNA labeling with propidium iodide, a fluorescent intercalating dye
that allows DNA quantification. Apoptotic nuclei appeared as a
broad hypodiploid DNA peak (black arrow in each panel) easily
discriminable from the narrow peak of nuclei with normal diploid DNA
counted in the red fluorescence channel. DNA fragmentation has been
detected in 5% of mock-infected human M/M (A).
Results in the same range were observed in HIV-infected M/M (9.1% of
propidium-positive cells; B), in mock-infected M/M
exposed to anti-NGF Ab (6.9%; C), or in HIV-infected
M/M treated with the IgG isotypic Ab (8.7%; E). By
contrast, exposure of HIV-infected cells to anti-NGF Ab
(D) induces DNA fragmentation in 40.3% of M/M in this
experiment representative of five different tests.
(Right) TUNEL. Immunocytochemical studies performed by
TUNEL show nuclei with round condensed chromatin in HIV-infected M/M
exposed to anti-NGF Ab (D) far more than in any of the
other M/M samples tested (A, B,
C, and E). The figure presents data from
a typical experiment of three.