Expansion and apoptosis of adoptively transferred CD4⁺ T cells. (A) Changes of DO11.10 cell frequency among CD4⁺ T cells in LN of BALB/c (○) or plt/plt (•) mice after immunization. (B) Annexin V⁺ cells in each division of transferred DO11.10 CD4⁺ T cells were detected after immunization, and results at day 11 are representatively depicted. The number of dividing time of DO11.10 CD4⁺ T cells is indicated in each column. (C,E) Quantitative comparison of annexin V⁺ DO11.10 CD4⁺ T cells in each division between BALB/c (□) and plt/plt (⊡) mice at day 5 (C) and day 11 (E). (D,F) The percentage of DO11.10 CD4⁺ T cells in each division in LN cells of BALB/c (□) and plt/plt (⊡) mice at day 5 (D) day 11 (F). Mean ± SD for 3 mice per group is given in panels C,E-F. Asterisk indicates significant difference by Student t test (P < .05) between BALB/c and plt/plt mice.