CD40L-OX40L combination maintains CD4 T cells in culture and increases the proportion of CD45RO-expressing CD4 and CD8 T cells. (A) Mean ± SD percentage of CD4⁺ cells for each condition tested. (B-C) Mean + SD percentages of CD4 (▦) and CD8 (▪) positive for CD45RO and CD62L, respectively. ^*Significant difference (P < .05). (D) Percentages of CD8 T cells positive for CD56. For all panels, expression at time 0 is compared with expression for each condition at week 3.