Density plots of chemokine receptor expression by Treg.

<p>Representative density plots of CCR4 and CCR7 expression by BALF Treg. The parent populations for determination of chemokine receptor positivity were singlet, live, CD3⁺CD4⁺CD25^hiFoxp3⁺ lymphocytes as shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0011354#pone-0011354-g001" target="_blank">Figure 1</a>. (left) Demonstrates the generally high level of CCR4 expression by Treg. The CCR4 gate was determined such that <0.1% of the cells were positive in the CCR4 FMO tube (see text for detail). (right) Demonstrates the variability of CCR7 expression by Treg. The CCR7 gate was determined such that <0.3% of the cells were positive in the CCR7 FMO tube.