Thymus, spleen, and LN volumes.

Shown are volumes of thymus (left panel), spleen (middle panel), and LNs (right panel) in IL-7–treated (filled symbols) and placebo-treated (open symbols) animals at 6, 10, and 14 weeks after transplantation. Each LN volume represents the sum of volumes of one right axillary LN, one left axillary lymph node, one pelvic LN, one right inguinal LN, and one left inguinal lymph node, as explained in “Materials and methods.” The animals were treated with IL-7 or placebo between 6 and 10 weeks after transplantation, as indicated in each graph by the horizontal black bar.