GEOapplication/xmlftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE314nnn/GSE314181/suppl/GSE314181_abundance.kraken2.tsv.gzftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE314nnn/GSE314181/suppl/GSE314181_methylation.comp.csv.gzftp://ftp.ncbi.nlm.nih.gov/geo/series/GSE314nnn/GSE314181/primaryOK200OtherMus musculusOtherhttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE314181GEOGSEfalseMaternal trans-vaccenic acid reshapes neonatal T cell development and immune imprinting (LIME-seq)How maternal nutrition influences neonatal immune development and imprinting through breastfeeding remains largely unclear. Here, we report that maternal supplementation with 25 trans-vaccenic acid (TVA) – the predominant naturally occurring trans-fatty acid in human breast milk (HBM) – promotes neonatal T cell development in mice, particularly expanding the naïve CD4+ T cell population with enhanced readiness. This implements a shift from T helper (Th)2- biased neonatal immune responses to Th1-skewing, resulting in improved adaptive immunity against viral infection and lung inflammation. Mechanistically, TVA via breastfeeding reprograms neonatal naïve CD4+ 30 T cells through a G protein coupled receptor (GPR43)-CCCTC-binding factor axis for enhanced cooperation with transcription factor TBX21, which also exhibits a longlasting immune imprinting effect. Furthermore, TVA levels in HBM from mothers of preterm infants inversely correlate with the incidence of inflammation-associated bronchopulmonary dysplasia in their preterm infants. Our findings establish the multifaceted benefits of maternal 35 nutrition and breastfeeding via TVA in promoting infant immune homeostasis and protective immunity.2026/06/22GSE314181GSM9383512GSM9383513GSM9383514GSM9383505GSM9383506GSM9383507GSM9383508GSM9383509GSM9383510GSM938351134328314181Mus musculus