Authors:
Katja Lüthje, Axel Kallies, Yoko Shimohakamada, Gabrielle T Belz, Amanda Light, David M Tarlinton, & Stephen L Nutt
Summary:
Germinal centers require CD4+ follicular helper T cells (TFH cells), whose hallmark is expression of the transcriptional repressor Bcl-6, the chemokine receptor CXCR5 and interleukin 21 (IL-21). To track the development and fate of TFH cells, we generated an IL-21 reporter mouse by introducing sequence encoding green fluorescent protein (GFP) into the Il21 locus; these mice had expression of IL-21–GFP in CD4+CXCR5+PD-1+ TFH cells. IL-21–GFP+ TFH cells were multifunctional helper cells that coexpressed several cytokines, including interferon-γ (IFN-γ), IL-2 and IL-4. TFH cells proliferated and gave rise to transferrable memory cells with plasticity, which differentiated after recall into conventional effector helper T cells and TFH cells. Thus, we demonstrated that TFH cells were not terminally differentiated but instead retained the flexibility to be recruited into other helper T cell subsets and nonlymphoid tissues.
Source:
Nature Immunology; 13, 491-498 (04/01/12)