The immunological profile of RC17 hESC-derived dopaminergic neural progenitor cells in vitro: Implications for the STEM-PD clinical trial

Summary

Parkinson's disease involves the progressive loss of dopaminergic neurons, prompting clinical trials replacing cell loss with neural grafts. This includes the transplantation of pluripotent stem cell-derived mesencephalic dopaminergic neural progenitors (mesDAp), including the RC17 human embryonic stem cell (hESC)-derived cells currently under investigation in the European STEM-PD trial (NCT05635409). To assess potential immune rejection risk, we characterized RC17-mesDAp immunogenicity in vitro, comparing them to human fetal ventral mesencephalic tissue (hfVM), as successfully used in similar clinical trials such as TRANSEURO. Although RC17-mesDAp expressed MHC class I, upregulated by pro-inflammatory cytokines, no peripheral immune response was detected in vitro. Instead, cells exhibited immunomodulatory effects, reducing T cell CD25 expression and proliferation. Transcriptomic analysis showed that both RC17-mesDAp and hfVM upregulated antigen-processing pathways in response to IFN-γ yet remained non-immunogenic. Findings support the immunological safety of RC17-mesDAp and suggest a set of in vitro assays that may be applicable for the preclinical evaluation of other human stem cell therapies. Copyright © 2026 The Authors. Published by Elsevier Inc. All rights reserved.

Authors Curle AJ, Fazal SV, Qarin S, Howlett SK, He X, Stamper A, Pisupati V, Barker RA, Jones JL
Journal Stem cell reports
Publication Date 2026 Mar 10;21(3):102818
PubMed 41687623
PubMed Central PMC12985363
DOI 10.1016/j.stemcr.2026.102818

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