Fig. 7.
Photomicrographs (1,000 × magnification) showing perforin expression in cytoplasmic granules. PBL from adults: (A) time 0; (B) 24 hours IL-2 culture. PBL from elderly persons: (C) time 0; (D) 24 hours IL-2 culture. Arrows in (C) indicate granules in the cytoplasm of elderly persons stained light, but clearly positive for perforin.