CD95/Fas and mitochondria copolarization in early steps of CD95/Fas-induced apoptosis of HIV-specific CD8⁺ T cells. (A) Purified CD8⁺ T cells from an HIV⁺ individual were left untreated or treated with a mouse anti-CD95/Fas antibody for 1 hour at 37°C. Following fixation, a double-staining protocol was performed. Localization of CD95/Fas and mitochondria was analyzed by confocal microscopy. Representative 3D images are shown from 1 of 3 experiments performed. Untreated cells are shown on the left; right panels depict 2 cells showing copolarization. (B) Representative 3D confocal image showing CD95/Fas and mitochondria localization in sorted HIV-specific CD8⁺ T cells treated with anti-CD95/Fas antibody. CD95/Fas capping is accompanied with copolarization of mitochondria (arrow).