Characterization of the Impact of Daclizumab Beta on Circulating Natural Killer Cells by Mass Cytometry.

Thanmayi Ranganath,Laura J Simpson,Nancy Zhao,Susan Holmes,Catherine A Blish,Christof Seiler,Anne-Maud Ferreira,Elena Vendrame,Jason D Fontenot

doi:10.3389/fimmu.2020.00714

Thanmayi Ranganath, Laura J Simpson + Show 7 more

Open Access

https://doi.org/10.3389/fimmu.2020.00714

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Abstract

Daclizumab beta is a humanized monoclonal antibody that binds to CD25 and selectively inhibits high-affinity IL-2 receptor signaling. As a former treatment for relapsing forms of multiple sclerosis (RMS), daclizumab beta induces robust expansion of the CD56bright subpopulation of NK cells that is correlated with the drug’s therapeutic effects. As NK cells represent a heterogeneous population of lymphocytes with a range of phenotypes and functions, the goal of this study was to better understand how daclizumab beta altered the NK cell repertoire to provide further insight into the possible mechanism(s) of action in RMS. We used mass cytometry to evaluate expression patterns of NK cell markers and provide a comprehensive assessment of the NK cell repertoire in individuals with RMS treated with daclizumab beta or placebo over the course of 1 year. Treatment with daclizumab beta significantly altered the NK cell repertoire compared to placebo treatment. As previously reported, daclizumab beta significantly increased expression of CD56 on total NK cells. Within the CD56bright NK cells, treatment was associated with multiple phenotypic changes, including increased expression of NKG2A and NKp44, and diminished expression of CD244, CD57, and NKp46. These alterations occurred broadly across the CD56bright population, and were not associated with a specific subset of CD56bright NK cells. While the changes were less dramatic, CD56dim NK cells responded distinctly to daclizumab beta treatment, with higher expression of CD2 and NKG2A, and lower expression of FAS-L, HLA-DR, NTB-A, NKp30, and Perforin. Together, these data indicate that the expanded CD56bright NK cells share features of both immature and mature NK cells. These findings show that daclizumab beta treatment is associated with unique changes in NK cells that may enhance their ability to kill autoreactive T cells or to exert immunomodulatory functions.

Highlights

Natural killer (NK) cells are innate lymphocytes that are best known for the eponymous function: that of killing other cells
Using Uniform Manifold Approximation and Projection (UMAP) visualization, we found an increase in frequency of CD56bright NK cells by 24 weeks of daclizumab beta treatment, which continued to increase at 52 weeks (Figure 1C)
We used mass cytometry to profile the NK cells expanded in the setting of daclizumab beta treatment of relapsing forms of multiple sclerosis (RMS)

Summary

Introduction

Natural killer (NK) cells are innate lymphocytes that are best known for the eponymous function: that of killing other cells. NK cell function is controlled by signals received through activating, inhibitory and cytokine receptors [1]. Activating receptors, examples of which include the natural cytotoxicity receptors NKp30, NKp44, and NKp46, the C-type lectin receptors NKG2D and NKG2C, and certain classes of activating Killercell Immunoglobulin-like Receptors (KIRs), generally sense stress on the target cell and promote NK cell activation. Inhibitory receptors, including most KIRs, NKG2A, and LILRB1 (CD85j), generally recognize Major Histocompatibility Class (MHC) I receptors and dampen NK cell responses to normal healthy cells. The mature CD56dim NK cells are the predominant subset and have potent cytotoxic activity, while the relatively immature CD56bright NK cells are generally present at

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