A subset of UL138 specific CD4+ T cells express phenotypic hallmarks of T_reg cells.

<p>CD4+ T cells specific to UL138 (A) or gB (B) from 3 donors were expanded <i>in vitro</i> for 14 days and then stained for stable surface expression of CD25 (C). Numbers in the top right quadrant represent percentage of CD4⁺ CD25^hi cells (A and B). Error bars represent standard error of the mean (n = 3); Statistical analysis was performed using the students t test (C). PBMC were stained directly <i>ex vivo</i> for surface expression of CD25 and intracellular expression of FoxP3 or using an isotype control (D). Quadrant numbers represent percentage of CD4⁺ cells. In vitro expanded cells from two donors, specific to UL138 and gB (CMV305) or UL138, LUNA and gB (CMV300) were stained for expression of CD4, CD25 and FoxP3 (E). CD4+ CD25hi cells were analysed for expression of FoxP3.