Selective expansion of regulatory T cells using an orthogonal IL-2/IL-2 receptor system facilitates transplantation tolerance
Toshihito Hirai, … , K. Christopher Garcia, Robert S. Negrin
Toshihito Hirai, … , K. Christopher Garcia, Robert S. Negrin
Published April 15, 2021
Citation Information: J Clin Invest. 2021;131(8):e139991. https://doi.org/10.1172/JCI139991.
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Selective expansion of regulatory T cells using an orthogonal IL-2/IL-2 receptor system facilitates transplantation tolerance

Abstract

Adoptive transfer of Tregs has been shown to improve alloengraftment in animal models. However, it is technically challenging to expand Tregs ex vivo for the purpose of infusing large numbers of cells in the clinic. We demonstrate an innovative approach to engineering an orthogonal IL-2/IL-2 receptor (IL-2R) pair, the parts of which selectively interact with each other, transmitting native IL-2 signals, but do not interact with the natural IL-2 or IL-2R counterparts, thereby enabling selective stimulation of target cells in vivo. Here, we introduced this orthogonal IL-2R into Tregs. Upon adoptive transfer in a murine mixed hematopoietic chimerism model, orthogonal IL-2 injection significantly promoted orthogonal IL-2R+Foxp3GFP+CD4+ cell proliferation without increasing other T cell subsets and facilitated donor hematopoietic cell engraftment followed by acceptance of heart allografts. Our data indicate that selective target cell stimulation enabled by the engineered orthogonal cytokine receptor improves Treg potential for the induction of organ transplantation tolerance.

Authors

Toshihito Hirai, Teresa L. Ramos, Po-Yu Lin, Federico Simonetta, Leon L. Su, Lora K. Picton, Jeanette Baker, Jian-Xin Lin, Peng Li, Kinya Seo, Juliane K. Lohmeyer, Sara Bolivar-Wagers, Melissa Mavers, Warren J. Leonard, Bruce R. Blazar, K. Christopher Garcia, Robert S. Negrin

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Figure 2

Ortho IL-2 selectively expands oIL-2Rβ–transduced Tregs without affecting cocultured naive T cells or reducing Treg functions.

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Ortho IL-2 selectively expands oIL-2Rβ–transduced Tregs without affectin...
Naive Thy1.1+ Tcons were cocultured with Thy1.2+Foxp3GFP+ Tregs that were transduced with oIL-2Rβ (oTregs; transduction efficiency was ~30%). Flow cytometry analyses performed after 4-day coculture. (A) Representative histograms show expression levels of CD25 and ICOS and dilution of proliferation dye on Thy1.1+ Tcons. (B) Representative pseudocolor plots show the proportion of Foxp3GFP+ cells (oTreg: upper gate) and CD25hiThy1.1+ Tcons (lower gate). Gray, no IL-2; orange, WT IL-2 (1 × 103 IU/mL); red, ortho IL-2 (1 × 105 IU/mL). Box plots showing CD25 MFI (C) and percentage of proliferation (D) in Thy1.1+ Tcons. Thy1.1+ Tcon alone is shown as no suppression control (Treg [–], white box). P values in yellow/red on the columns were calculated between Tcon alone control and coculture at each IL-2 concentration. (E) Box plots showing CD25 MFI in oTregs. (F) Cell number per well relative to no IL-2 control in Thy1.1+ Tcons (black line) or oTregs (green line) with mean plus 95% confidence intervals. P values calculated between Thy1.1+ Tcons and oTreg at each IL-2 concentration are shown. (G) Box plots showing percentage of oTregs per well. P values were calculated between no IL-2 control and each IL-2 concentration. Quantification of triplicate wells in 1 representative experiment of 3 independent experiments. **P < 0.01; ***P < 0.001, Welch’s 2-sample t test. WT and ortho IL-2: 1 IU = 312.5 ng.