OBJECTIVE: Naturally occurring CD4+,CD25+ Treg cells are central in the maintenance of peripheral tolerance. Impaired activity and/or a lower frequency of these cells is involved in the emergence of autoimmunity. We undertook this study to analyze relative proportions and functional alterations of Treg cells in MRL/lpr mice. METHODS: The frequency of CD4+,CD25+ T cells in the peripheral blood of healthy and autoimmune mice was compared by flow cytometry. The capacity of CD4+,CD25+ T cells to inhibit the proliferation and cytokine secretion of CD4+,CD25- T cells was assessed after polyclonal activation. RESULTS: MRL/lpr mice exhibited a normal percentage of CD4+,CD25 high T cells, and forkhead box P3 messenger RNA and protein expression in Treg cells was not altered. However, MRL/lpr Treg cells displayed a reduced capacity to suppress proliferation and to inhibit interferon-gamma secretion by syngeneic effector CD4+,CD25- T cells, as compared with syngeneic cocultures of CBA/J T cells. Moreover, effector MRL/lpr CD4+,CD25- T cells were substantially less susceptible to suppression even when cultured with CBA/J or MRL/lpr Treg cells. Crossover experiments led us to conclude that in MRL/lpr mice, each partner engaged in T cell regulation displays altered functions. Molecules involved in suppressive mechanisms (CTLA-4 and CD80/CD86) are underexpressed, and antigen-presenting cells (APCs) produce raised levels of interleukin-6, which is known to abrogate suppression. CONCLUSION: Our results suggest that although the frequency and phenotype of Treg cells in MRL/lpr mice are similar to those in normal mice, Treg cells in MRL/lpr mice are not properly stimulated by APCs and are unable to suppress proinflammatory cytokine secretion from effector T cells.
OBJECTIVE: Naturally occurring CD4+,CD25+ Treg cells are central in the maintenance of peripheral tolerance. Impaired activity and/or a lower frequency of these cells is involved in the emergence of autoimmunity. We undertook this study to analyze relative proportions and functional alterations of Treg cells in MRL/lpr mice. METHODS: The frequency of CD4+,CD25+ T cells in the peripheral blood of healthy and autoimmune mice was compared by flow cytometry. The capacity of CD4+,CD25+ T cells to inhibit the proliferation and cytokine secretion of CD4+,CD25- T cells was assessed after polyclonal activation. RESULTS: MRL/lpr mice exhibited a normal percentage of CD4+,CD25 high T cells, and forkhead box P3 messenger RNA and protein expression in Treg cells was not altered. However, MRL/lpr Treg cells displayed a reduced capacity to suppress proliferation and to inhibit interferon-gamma secretion by syngeneic effector CD4+,CD25- T cells, as compared with syngeneic cocultures of CBA/J T cells. Moreover, effector MRL/lpr CD4+,CD25- T cells were substantially less susceptible to suppression even when cultured with CBA/J or MRL/lpr Treg cells. Crossover experiments led us to conclude that in MRL/lpr mice, each partner engaged in T cell regulation displays altered functions. Molecules involved in suppressive mechanisms (CTLA-4 and CD80/CD86) are underexpressed, and antigen-presenting cells (APCs) produce raised levels of interleukin-6, which is known to abrogate suppression. CONCLUSION: Our results suggest that although the frequency and phenotype of Treg cells in MRL/lpr mice are similar to those in normal mice, Treg cells in MRL/lpr mice are not properly stimulated by APCs and are unable to suppress proinflammatory cytokine secretion from effector T cells.
Authors: Nicole L Regna; Miranda D Vieson; Alexander M Gojmerac; Xin M Luo; David L Caudell; Christopher M Reilly Journal: Int Immunopharmacol Date: 2015-10-21 Impact factor: 4.932
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Authors: Kailin Yan; Qiang Cao; Christopher M Reilly; Nicolas L Young; Benjamin A Garcia; Nilamadhab Mishra Journal: J Biol Chem Date: 2011-06-27 Impact factor: 5.157
Authors: B T Stocks; A J Wilhelm; C S Wilson; A F Marshall; N E Putnam; A S Major; D J Moore Journal: Am J Transplant Date: 2015-09-15 Impact factor: 8.086