Fig. 1.

CXCR5-dependent regulation of germinal center formation by Treg cells. Naïve CD4⁺CD25^–GITR^–CD62L^hiCD44^lo T cells isolated from wild-type (WT) mice were mixed with CD4⁺CD25^hi Treg cells isolated from WT or CXCR5^−/− mice and adoptively transferred into Tcrb^−/− mice. Twenty four hours later, the recipient mice were s.c. immunized with KLH in CFA. Seven days after immunization, germinal center formation (PNA) and CD4⁺ T cell localization (CD4) in the draining lymph node of the recipient mice were analyzed. Dotted areas represent germinal centers.