FIG 5.

Expansion of Tregs following primary intradermal infection is sustained. Eight mice were infected intradermally with 10² T. congolense parasites weekly (for 2 consecutive weeks). One week after the last infection, some mice (n = 4) were sacrificed to determine the baseline levels of Tregs. The remaining mice (n = 4) and some age-matched naive controls were challenged (chall. inf.) intradermally with 10³ T. congolense parasites and sacrificed 4 days postchallenge to determine the levels of Tregs. Shown are the percentages of CD4⁺ CD25⁺ Foxp3⁺ cells (Tregs) in the spleens (A) and the lymph nodes (B) draining the infection site, presented as percent fold increase over the level in naive (uninfected) mice. pri. inf., primary infection. The data presented are representative of 2 different experiments with similar results. Error bars show means ± SEM. *, P < 0.05; **, P < 0.01. ns, not significant.