Aberrant lymphoid aggregates of the stomach support recirculation of naive lymphocytes independently of CD62L expression. Biotinylated splenocytes (2-3 × 10⁷) derived from wt or CCR7^−/− mice were adoptively transferred without or together with anti-CD62L or IgG2a antibody (Ab) (as indicated) into adult CCR7^−/− mice. Spleens and the draining iLNs contained biotinylated wt cells (transferred with or without IgG2a Ab) 3 hours (data not shown), 24 hours (A-B), and 5 days (C) after injection, as assessed by staining with Streptavidin-AP in red and flow cytometric analysis (A; representative FACS analyses for 3 to 5 experiments are shown). Comparable numbers of biotinylated wt cells ± IgG2a Ab, CCR7^−/−, and wt cells + anti-CD62L Ab were found in the spleens, but significantly less CCR7^−/− and wt cells + anti-CD62L Ab than wt cells ± IgG2a Ab could be retrieved from the draining LNs (A). Homing of biotinylated wt cells ± IgG2a Ab (red) in follicular aggregates in CCR7^−/− mice was seen at all time points analyzed here (B; marked by arrows). CCR7^−/− cells were observed at a significantly lower frequency at 3 hours (data not shown) and 24 hours (B; marked by arrows) after injection, whereas wt cells + anti-CD62L Ab were found in comparable numbers than were wt cells ± IgG2a Ab at 24 hours (B; marked by arrows) after injection. At 5 days after injection follicular aggregates contained comparable numbers of transferred biotinylated CCR7^−/−, wt ± IgG2a antibody, and wt cells + anti-CD62L Ab (C) as visualized by Streptavidin-AP reactivity and HE-counterstaining in frozen sections. Original magnification, ×200. Data are representative of 3 to 5 mice in each group (B-C).