CD45 ligation expands Tregs by promoting interactions with DCs
Geoffrey Camirand, … , Christopher E. Rudd, David M. Rothstein
Geoffrey Camirand, … , Christopher E. Rudd, David M. Rothstein
Published September 9, 2014
Citation Information: J Clin Invest. 2014;124(10):4603-4613. https://doi.org/10.1172/JCI74087.
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CD45 ligation expands Tregs by promoting interactions with DCs

Abstract

Regulatory T cells (Tregs), which express CD4 and FOXP3, are critical for modulating the immune response and promoting immune tolerance. Consequently, methods to expand Tregs for therapeutic use are of great interest. While transfer of Tregs after massive ex vivo expansion can be achieved, in vivo expansion of Tregs would be more practical. Here, we demonstrate that targeting the CD45 tyrosine phosphatase with a tolerogenic anti-CD45RB mAb acutely increases Treg numbers in WT mice, even in absence of exogenous antigen. Treg expansion occurred through substantial augmentation of homeostatic proliferation in the preexisting Treg population. Moreover, anti-CD45RB specifically increased Treg proliferation in response to cognate antigen. Compared with conventional T cells, Tregs differentially regulate their conjugation with DCs. Therefore, we determined whether CD45 ligation could alter interactions between Tregs and DCs. Live imaging showed that CD45 ligation specifically reduced Treg motility in an integrin-dependent manner, resulting in enhanced interactions between Tregs and DCs in vivo. Increased conjugate formation, in turn, augmented nuclear translocation of nuclear factor of activated T cells (NFAT) and Treg proliferation. Together, these results demonstrate that Treg peripheral homeostasis can be specifically modulated in vivo to promote Treg expansion and tolerance by increasing conjugation between Tregs and DCs.

Authors

Geoffrey Camirand, Ying Wang, Yuning Lu, Yisong Y. Wan, Yan Lin, Songyan Deng, Galip Guz, David L. Perkins, Patricia W. Finn, Donna L. Farber, Richard A. Flavell, Warren D. Shlomchik, Fadi G. Lakkis, Christopher E. Rudd, David M. Rothstein

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Figure 4

Anti-CD45RB increases Tregs by augmenting HP of nTregs.

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Anti-CD45RB increases Tregs by augmenting HP of nTregs. (A) Flow cytomet...
(A) Flow cytometry plots of live CD4+ cells recovered after adoptive transfer of highly purified FOXP3+CD4+Thy1.1+ cells (obtained as in Figure 3A) into control IgG- or anti-CD45RB–treated WT congenic mice (examined in spleen on day 10). Numbers indicate average (± SD) percentage of transferred cells (Thy1.1+CD4+), FOXP3 expression within transferred cells, and CFSE dilution among FOXP3+-transferred cells (n = 8 mice per group, 4 independent experiments). *P < 0.05 vs. control IgG. (B) Number of recovered FOXP3+ cells from right column in A, relative to control IgG. (C) Distribution (CFSEbright vs. CFSElo) of increased FOXP3+ cells in response to anti-CD45RB treatment over control IgG from right column in A. Squares represent individual mice, and bars show averages. (D) Flow cytometry plot of CFSE dilution profiles of FOXP3–CD4+ and FOXP3+CD4+ cells recovered after transfer of total CD4+ T cells into congenic mice that were untreated or treated with anti-CD45RB (examined in spleens on day 10; n = 10 mice per group, 4 independent experiments). Numbers represent average (± SD) percentage of CFSElo. *P < 0.05 vs. untreated. (E) Number of CFSEbright and CFSElo cells from D, relative to control IgG. (F) Flow cytometry histograms and average (± SD) percentage of BrdU incorporation in endogenous FOXP3– and FOXP3+CD4+ cells from untreated and anti-CD45RB–treated mice (day 10). Mice were fed BrdU on days 7–10 (n = 4 mice per group, 2 experiments; *P = 0.01 vs. untreated).