T regulatory cell chemokine production mediates pathogenic T cell attraction and suppression
Scott J. Patterson, Anne M. Pesenacker, Adele Y. Wang, Jana Gillies, Majid Mojibian, Kim Morishita, Rusung Tan, Timothy J. Kieffer, C. Bruce Verchere, Constadina Panagiotopoulos, Megan K. Levings
Scott J. Patterson, Anne M. Pesenacker, Adele Y. Wang, Jana Gillies, Majid Mojibian, Kim Morishita, Rusung Tan, Timothy J. Kieffer, C. Bruce Verchere, Constadina Panagiotopoulos, Megan K. Levings
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Research Article Immunology

T regulatory cell chemokine production mediates pathogenic T cell attraction and suppression

Abstract

T regulatory cells (Tregs) control immune homeostasis by preventing inappropriate responses to self and nonharmful foreign antigens. Tregs use multiple mechanisms to control immune responses, all of which require these cells to be near their targets of suppression; however, it is not known how Treg-to-target proximity is controlled. Here, we found that Tregs attract CD4+ and CD8+ T cells by producing chemokines. Specifically, Tregs produced both CCL3 and CCL4 in response to stimulation, and production of these chemokines was critical for migration of target T cells, as Tregs from Ccl3–/– mice, which are also deficient for CCL4 production, did not promote migration. Moreover, CCR5 expression by target T cells was required for migration of these cells to supernatants conditioned by Tregs. Tregs deficient for expression of CCL3 and CCL4 were impaired in their ability to suppress experimental autoimmune encephalomyelitis or islet allograft rejection in murine models. Moreover, Tregs from subjects with established type 1 diabetes were impaired in their ability to produce CCL3 and CCL4. Together, these results demonstrate a previously unappreciated facet of Treg function and suggest that chemokine secretion by Tregs is a fundamental aspect of their therapeutic effect in autoimmunity and transplantation.

Authors

Scott J. Patterson, Anne M. Pesenacker, Adele Y. Wang, Jana Gillies, Majid Mojibian, Kim Morishita, Rusung Tan, Timothy J. Kieffer, C. Bruce Verchere, Constadina Panagiotopoulos, Megan K. Levings

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Figure 7

Tregs from the blood of subjects with established T1D have decreased CCL3 and CCL4 production.

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Tregs from the blood of subjects with established T1D have decreased CCL...
(A) Tregs and Tconv cells were sorted from the blood of healthy adults, and 1 × 106/ml were stimulated with α-CD3/α-CD28–coated beads in the presence of IL-2. After 48 hours, the amounts of CCL3, CCL4, and IFN-γ in supernatants were determined. The background of the respective unstimulated samples was subtracted; shown are the means ± SEM for 3 individuals. (B) Activated Tregs and Tconv cells were restimulated with PMA/ionomycin, and the proportions of live, single cells producing CCL3, CCL4, or IFN-γ were determined. Shown are representative plots and mean ± SEM for 8 individuals with the background of the respective unstimulated sample subtracted. (C) FACS-sorted peripheral blood Tconv cells and Tregs from adult controls (n = 15, mean with SD) were activated with α-CD3/α-CD28–coated beads in the presence of IL-2 for 48 hours at a cell concentration of 1.4 × 105/ml (left panel) or 1.4 × 105/ml (right panel). FACS-sorted peripheral blood Tregs from pediatric controls (n = 17–18), established T1D (est) (n = 18–22), new-onset T1D (new) (n = 15–17), and JIA (n = 13) patients were activated with α-CD3/α-CD28–coated beads in the presence of IL-2 for 48 hours at a cell concentration of 1.4 × 105/ml. For C and D, supernatants were collected and CCL3, CCL4, and IFN-γ were assessed by CBA. Background measurements in the unstimulated sample were subtracted, and outliers were excluded by the ROUT method (Q = 1%); 1-way ANOVA with Bonferroni’s post-hoc test. *P < 0.05; **P < 0.01; ***P < 0.001.