CD4⁺CD3⁻ cells found around the central arteriole in the spleen and associated with PNAd⁺ HEVs in the lymph node. Confocal images of T-cell–deficient mouse spleens stained with B220 and CD11c in green, and CD4 in red (A), and normal mouse spleens stained with CD3, B220, and CD11c in green and CD4 in red (B). Area indicated by closed yellow line identifies central arteriole in high magnification images of panels A and B. (C) Confocal images of lymph node from a normal mouse stained with CD3, B220, and CD11c in green, CD4 in red, IgM in gray, and PNAd in blue. Scale bar represents 100 μm for low magnification (10×), and 20 μm for high magnification (63×).