Regulatory T-cells (Tregs) are vital for maintaining immunological self-tolerance, and the transcription factor FOXP3 is considered critical for their development and function. Peripheral Treg induction may significantly contribute to the total Treg pool in healthy adults, and this pathway may be enhanced in thymic-deficient conditions like multiple sclerosis (MS). Here, we evaluated iTreg formation from memory versus naïve CD4+CD25− T-cell precursors. We report the novel finding that memory T-cells readily expressed CD25 and FOXP3, and demonstrated significantly greater suppressive function. Additionally, the CD25−FOXP3− fraction of stimulated memory T-cells also displayed robust suppression not observed in naïve counterparts or ex vivo resting (CD25−) T-cells. This regulatory population was present in both healthy subjects and clinically-quiescent MS patients, but was specifically deficient during disease exacerbation. These studies indicate that iTreg development and function are precursor dependent. Furthermore, MS quiescence appears to correlate with restoration of suppressive function in memory-derived CD4+CD25−FOXP3− iTregs.
CD4+CD25+FOXP3+ regulatory T-cells (Tregs) play a vital role in suppressing autoimmune responses. We have previously shown that, in humans, all activated T-cells attain a state of transient FOXP3 expression that correlates with transient suppressive ability. In fact, peripheral generation of induced Tregs (iTregs) is likely the dominant source of regulatory cells in healthy adults. Through the use of a sensitive flow-based suppression assay, we observed that both memory and naïve CD4+CD25-FOXP3- T-cells developed regulatory ability following a variety of activating stimuli. This suppressive ability was not due to competition for nutrients or antigen presenting cells. Interestingly, memory T-cells displayed significantly greater FOXP3 induction compared to naïve counterparts, and this phenotype correlated to significantly enhanced suppressive function. Furthermore, acquisition of suppressive ability in both the memory and naïve iTreg compartments was proportional to the strength of activating stimulus. While blockade of activation using anti-IL-2, CTLA-4 Ig, anti-TGF-B, indomethacin or cyclosporin A did not affect iTreg generation, methotrexate drastically preempted the induction of regulatory ability. Moreover, irradiation of iTregs also abrogated regulatory function. These studies suggest that iTreg development and function may vary dependent on precursor origin and emphasize the importance of characterizing the iTreg compartment prior to therapeutic application.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.