Immunotherapy of Non-Infectious Uveitis using Collagen II-specific regulatory Type 1 (Col-Treg) cells

Abstract

Purpose: Non-infectious uveitis(NIU) is a condition characterized by dysregulation of the immune system in the eye for which only steroids are currently approved. Col-Treg is a T-cell immunotherapy composed of autologous type-1 regulatory T (Treg) cells specific for collagen-II. The use of Col-Treg was evaluated for NIU in mice as Collagen-II is naturally present in the eye and so triggers the activity of the Col-Treg cells in situ.

Methods: Col-Treg cells were produced from blood of healthy volunteers or from splenocytes of transgenic mice for Collagen-II-specific TCR. Cells were characterized for marker expression by FACS and for in vitro immuno-modulatory functions. NIU model was developed by IRBP immunization. In vivo efficacy was evaluated using ophtalmoscopy and histology. In vivo tracking was performed using a Col-Treg TCR Vβ chain-specific quantitative PCR.

Results: Col-Treg cells secrete IL-10 and IL-13 and express GITR, CD39 and Granzyme B, molecules known to be involved in the control of inflammation. In vitro assays confirmed the capacity of Col-Treg cells to hydrolyse ATP, kill myeloid cells in a contact-dependent manner and inhibit T effector cell IL-17 and IFNγ secretion using soluble factor dependent pathways. Intravenous administration of Col-Treg inhibited ocular inflammation in NIU mice. Moreover, Col-Treg injection decreased cell infiltration in the ocular tissues, vasculitis and retinal folds. Tracking experiments demonstrated a tropism of Col-Treg for inflammatory eyes. An in vivo GLP toxicity study performed in healthy mice did not reveal Col-Treg related adverse events. Characterization of human Col-Treg GMP batches demonstrated comparability with mouse Col-Treg for marker expression and in vitro function. Human Col-Treg cells did not show evidence of tumorigenicity or uncontrolled proliferation in vitro as witnessed by a limited survival capacity upon chronic stimulation and a strict dependence to exogenous stimulation for their exponential proliferation.

Conclusions: These results demonstrate the safety and efficacy of Col-Treg administration for the treatment of NIU in mice and suggest that Col-Treg could be used as a therapeutic tool for patients with non-infectious uveitis refractory to approved medications. These results will be taken as a basis for a First in Man clinical study with Col-Treg in NIU patients that is expected to start in 1H 2015.