IL-2 mutein selectively expands thymic memory Tregs with increased transendocytosis in healthy participants
Laura A. Cooney, Mitch Fahning, Liliane Khoryati, Anna Kus, Sheila Scheiding, Lori Blanchfield, Matt Lawrance, Basilin Benson, Kristina M. Harris, Gretchen A. Baltus, Shiuli Agarwal, Richard Wnek, Johannes F. Scheid, Kiki Cunningham-Bussel, Nancy D. Kim, S. Aubrey Stoch, Jyothsna Visweswaraiah, Nathan Higginson-Scott, Katalin Kis-Toth, Joanne L. Viney, Kevin L. Otipoby, Erik Sampson, Bridget Larkin, Daniel J. Campbell, S. Alice Long
Laura A. Cooney, Mitch Fahning, Liliane Khoryati, Anna Kus, Sheila Scheiding, Lori Blanchfield, Matt Lawrance, Basilin Benson, Kristina M. Harris, Gretchen A. Baltus, Shiuli Agarwal, Richard Wnek, Johannes F. Scheid, Kiki Cunningham-Bussel, Nancy D. Kim, S. Aubrey Stoch, Jyothsna Visweswaraiah, Nathan Higginson-Scott, Katalin Kis-Toth, Joanne L. Viney, Kevin L. Otipoby, Erik Sampson, Bridget Larkin, Daniel J. Campbell, S. Alice Long
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Research Article Clinical Research Immunology

IL-2 mutein selectively expands thymic memory Tregs with increased transendocytosis in healthy participants

Abstract

Tregs play an essential role in immune tolerance, and Treg-promoting therapies are in development for the treatment of many inflammatory disorders. IL-2–based therapies increase Treg frequency, but little is known about impacts on Treg heterogeneity and function. We extended analyses of an IL-2 mutein (MK-6194) single ascending dose trial in healthy human participants by comprehensively defining Treg subsets and gene expression changes in vitro and in vivo. We found highly specific and dose-dependent activation and expansion of Tregs in clinical and preclinical studies. Following a single subcutaneous dose in humans, thymus-derived Tregs were selectively activated and expanded, while peripherally induced Tregs were unaffected. Expanded Tregs had increased expression of genes and proteins consistent with activation, suppressor function, and homing to nonlymphoid tissue, as well as increased transendocytotic activity, as measured by CTLA-4–dependent capture of CD80 and CD86 from non-Tregs. These results shed light onto underlying mechanisms by which Treg-targeted therapy may promote immune tolerance.

Authors

Laura A. Cooney, Mitch Fahning, Liliane Khoryati, Anna Kus, Sheila Scheiding, Lori Blanchfield, Matt Lawrance, Basilin Benson, Kristina M. Harris, Gretchen A. Baltus, Shiuli Agarwal, Richard Wnek, Johannes F. Scheid, Kiki Cunningham-Bussel, Nancy D. Kim, S. Aubrey Stoch, Jyothsna Visweswaraiah, Nathan Higginson-Scott, Katalin Kis-Toth, Joanne L. Viney, Kevin L. Otipoby, Erik Sampson, Bridget Larkin, Daniel J. Campbell, S. Alice Long

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Figure 4

Prolonged, selective, dose-dependent pSTAT5 activation in Tregs following IL-2 mutein treatment in vivo.

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Prolonged, selective, dose-dependent pSTAT5 activation in Tregs followin...
(A) Schematic and representative plots for ex vivo pSTAT5 staining, gated on CD4+CD25+CD127– Tregs, for 1 participant at baseline versus day 8 after IL-2 mutein treatment (representative gating in Supplemental Figure 7A). Schematic generated in BioRender. (B) Frequency of pSTAT5+ cells among Tregs for all individuals, all time points (n as depicted in Figure 2A) when stained directly ex vivo without restimulation. Significance: *P < 0.05 versus placebo by mixed effects model with Dunnett’s correction for multiple comparisons; dose group reflected by color. (C) Log2-transformed average fold change in frequency of pSTAT5+ cells among various cell subsets from baseline to day 8 for 10 mg cohort (representative gating in Supplemental Figure 7A) when stained directly ex vivo without restimulation. Differences between baseline and day 8 determined using a Wilcoxon matched pairs signed rank test (n = 5). Cell types represented by shapes. (D) Schematic and representative plots for pSTAT5 staining of Tregs following in vitro restimulation with recombinant human IL-2 (rhIL-2) versus media alone for 1 sample. Schematic generated in BioRender. (E) Frequency of pSTAT5+ cells among Tregs for all cohorts, all doses following restimulation in vitro with rhIL-2; dose represented by color as in A. No significant differences by mixed effects model with Dunnett’s correction for multiple comparisons (n as depicted in Figure 2A).