Histological analysis of spleens of Tat-transgenic and control mice. Tat-transgenic mice (lines 21 and 29) and littermate control mice were killed at 12 to 15 months of age. Spleens were removed and processed for histology. Shown are the representative hematoxylin/eosin stains of (A) a control spleen (10×), (B) a Tat-transgenic spleen (10×), (C) a Tat-transgenic spleen at high magnification (25×).