Epigenetic instability and hypofunctionality of fetal Tregs allow a permissive regulatory environment for T effector memory maturation

J Jing Yao Leong (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) N Naomi McGovern (Centre for Trophoblast Research, Department of Pathology, University of Cambridge) A Archita Mishra (Singapore Immunology Network, Agency for Science, Technology and Research) M Martin Wasser (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) P Pavanish Kumar (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) S Shi Huan Tay (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) S Sharifah Nur Hazirah (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) J Joo Guan Yeo (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) X Xiu Qi Tan (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) N Nursyuhadah Sutamam (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) F Farah Nadiah Azman (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) C Camillus Jian Hui Chua (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) P Phyllis ZiXuan Chen (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) F Fauziah Ally (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) C Charles-Antoine Dutertre (Gustave Roussy Cancer Campus) L Lakshmi Ramakrishna (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) S Su Li Poh (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) L Liang Xie (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) Y Yiping Fan (Department of Reproductive Medicine, KK Women’s and Children’s Hospital) C Catherine Donner (Department of Obstetrics and Gynecology, Hôpital Erasme, Université Libre de Bruxelles) M Maria Papadopoulou (Department of Pharmacotherapy and Pharmaceutics, Université Libre de Bruxelles) D David Vermijlen (Department of Pharmacotherapy and Pharmaceutics, Université Libre de Bruxelles) T Thaschawee Arkachaisri (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia) J Jerry Kok Yen Chan F Florent Ginhoux S Salvatore Albani (Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia)

Abstract

The human gestational environment is commonly perceived to be predominantly suppressive and incompatible for T effector maturation. However, evidence of a competent effector fetal environment is mounting in the field. Here, we employed a high parametric, mass cytometry–based approach to study the fetal circulatory and microenvironmental immunomes, with the aim to understand the inception and extent of fetal effector T cell priming and its relation with regulatory mechanisms. We found evidence of fetal thymic immune imprinting, coupled with both circulatory and tissue effector memory development. Correspondingly, in the regulatory compartment, we detected the presence of Tbet + Treg in fetal tissues at elevated levels compared to adult tissues. Fetal Tregs, though capable of suppression, were hyposuppressive as compared with adult counterparts. We found that a proportion of fetal Tregs lost FoxP3 commitment during proliferation and exhibited higher TCR clonotype sharing with effector T cells, indicating higher plasticity in fetal Tregs than adult. Epigenetic profiling of the FoxP3 promoter locus reveals that fetal Tregs were only partially demethylated, possibly explaining the observed instability. In summary, our data provide evidence of a regulatory environment in the 2nd trimester permissive for T effector maturation, in part contributed by the relative instability and hypofunctionality in fetal Tregs.

Article Details

Volume / Issue Vol. 122, Issue 30
Published July 29, 2025
ISSN 0027-8424
Publisher National Academy of Sciences

Authors (26)

J

Jing Yao Leong

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

N

Naomi McGovern

Centre for Trophoblast Research, Department of Pathology, University of Cambridge

A

Archita Mishra

Singapore Immunology Network, Agency for Science, Technology and Research

M

Martin Wasser

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

P

Pavanish Kumar

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

S

Shi Huan Tay

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

S

Sharifah Nur Hazirah

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

J

Joo Guan Yeo

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

X

Xiu Qi Tan

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

N

Nursyuhadah Sutamam

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

F

Farah Nadiah Azman

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

C

Camillus Jian Hui Chua

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

P

Phyllis ZiXuan Chen

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

F

Fauziah Ally

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

C

Charles-Antoine Dutertre

Gustave Roussy Cancer Campus

L

Lakshmi Ramakrishna

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

S

Su Li Poh

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

L

Liang Xie

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

Y

Yiping Fan

Department of Reproductive Medicine, KK Women’s and Children’s Hospital

C

Catherine Donner

Department of Obstetrics and Gynecology, Hôpital Erasme, Université Libre de Bruxelles

M

Maria Papadopoulou

Department of Pharmacotherapy and Pharmaceutics, Université Libre de Bruxelles

D

David Vermijlen

Department of Pharmacotherapy and Pharmaceutics, Université Libre de Bruxelles

T

Thaschawee Arkachaisri

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia

J

Jerry Kok Yen Chan

F

Florent Ginhoux

S

Salvatore Albani

Translational Immunology Institute, Singhealth/Duke-National University of Singapore, Academic Medical Centre, The Academia