Kinetic of CD4 and CD8 proliferation in different lymphopenic hosts. (A,B) Cells from the blood, spleen, LN, and mesenteric LN at the indicated times after transfer were stained for Ly5.1 and CD4. The results are representative of 3 individual mice per group. The ratio of transferred donor cells was analyzed at every week after transfer. Shown are the mean ± SD of individually tested mice (n = 3). (C,D) Groups of Rag1^−/− and TCRb^−/− mice were transferred with naive Ly5.1 T cells, and killed at the indicated time points after the transfer. Total cell recovery as well as BrdU incorporation was determined as described in “Flow cytometry.” Shown are the mean ± SD of individually tested mice (n = 3). *P < .05; **P < .01.