Browsing by Subject "Tfh cells"

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    IL-10–producing Tfh cells accumulate with age and link inflammation with age-related immune suppression
    (American Association for the Advancement of Science, 2020-07-29) Almanan, Maha; Raynor, Jana; Ogunsulire, Ireti; Malyshkina, Anna; Mukherjee, Shibabrata; Hummel, Sarah A.; Ingram, Jennifer T.; Saini, Ankur; Xie, Markus M.; Alenghat, Theresa; Way, Sing Sing; Deepe, George S.; Divanovic, Senad; Singh, Harinder; Miraldi, Emily; Zajac, Allan J.; Dent, Alexander L.; Hölscher, Christoph; Chougnet, Claire; Hildeman, David A.; Microbiology and Immunology, School of Medicine
    Aging results in profound immune dysfunction, resulting in the decline of vaccine responsiveness previously attributed to irreversible defects in the immune system. In addition to increased interleukin-6 (IL-6), we found aged mice exhibit increased systemic IL-10 that requires forkhead box P3–negative (FoxP3−), but not FoxP3+, CD4+T cells. Most IL-10–producing cells manifested a T follicular helper (Tfh) phenotype and required the Tfh cytokines IL-6 and IL-21 for their accrual, so we refer to them as Tfh10 cells. IL-21 was also required to maintain normal serum levels of IL-6 and IL-10. Notably, antigen-specific Tfh10 cells arose after immunization of aged mice, and neutralization of IL-10 receptor signaling significantly restored Tfh-dependent antibody responses, whereas depletion of FoxP3+ regulatory and follicular regulatory cells did not. Thus, these data demonstrate that immune suppression with age is reversible and implicate Tfh10 cells as an intriguing link between “inflammaging” and impaired immune responses with age.
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    Transcription factor regulation of T helper subset function
    (2015-05-01) Awe, Olufolakemi O.; Kaplan, Mark H.; Blum, Janice S.; Zhou, Baohua; Travers, Jeffery B.
    The immune system protects the body from foreign organisms. T cells and B cells are integral components of the ability of the immune system to generate focused immune responses. The development of specialized subsets of T helper cells is governed by transcription factors. Previous work demonstrated a requirement for the transcription factor PU.1 in the development of IL-9-secreting Th9 cells. Work in this dissertation demonstrates that the Th9 subset is not stable in vitro, and that PU.1 expression decreases during long-term culture. To examine a role for PU.1 in Th9-independent immunity we examined a model of multiple sclerosis termed experimental autoimmune encephalomyelitis (EAE). Mice that lack PU.1 expression in T cells (Sfpi1lck-/- mice) demonstrated more severe disease with attenuated recovery compared to control mice, and this was accompanied by an increase of T cells in the central nervous system. We also observed that following multiple routes of immunization Sfpi1lck-/- mice had increased numbers of T follicular helper (Tfh) cells and increased germinal center responses. This correlated with increased expression of the cytokine IL-21 and the surface protein CD40L in T cells that lacked PU.1 expression and resulted in increased numbers of germinal center B cells and antigen-specific antibody titers compared to control mice. The increased germinal center B cells and antibody titers were attenuated with blocking CD40L antibody but not with neutralizing IL-21 antibody. These results suggest that PU.1 limits the expression of CD40L on Tfh cells to regulate the humoral immune response. Together, the data in this dissertation demonstrate Th9-independent functions of PU.1. Moreover, this work shows that transcription factors promoting the development of one subset of T helper cells can simultaneously have negative effects on distinct T cell lineages.