A single administration of E. coli LPS induced acute thymic atrophy with subsequent recovery. Groups of female BALB/c mice were treated with saline or LPS (100 μg i.p.) on day 0, and three mice per group were euthanized on days 1, 3, 7, 11, 15, 21, and 28 to monitor thymopoiesis. Mean thymus weight (A), absolute number of CD4/CD8 DP thymocytes (B), and molecules of mTREC per milligram of thymus tissue (C) ± SEM were determined at each harvest time. *, p ≤ 0.05 compared with saline-treated controls.