Fig 1: Vav1-Myo1f expression alters immune homeostasis and preferentially induces Th2 differentiation upon MAF upregulation(A) Representative fluorescence-activated cell sorting (FACS) plot showing CD4/CD8 staining and associated quantification of CD4+ T cells in spleen samples from Vav1WT/co-Vav1-Myo1f;CD4CreERT2 mice treated with vehicle (WT) or tamoxifen (TMX) (Vav1-Myo1f).(B and C) Representative histograms and associated quantification of CD69 (B) and ICOS (C) in splenic CD4+ T cells from Vav1WT/co-Vav1-Myo1f;CD4CreERT2 mice treated in vivo with vehicle (WT) or TMX (Vav1-Myo1f).(D–G) Representative FACS plots of lineage marker staining and associated quantification of PD1+CXCR5+ Tfh cells (D), CD25+FOXP3 Treg cells (E), CD44 and CD62L (F), and CXCR3 and CCR6 T helper markers (G) in splenic CD4+ T cells isolated from Vav1WT/co-Vav1-Myo1f;CD4CreERT2 mice treated in vivo with vehicle (WT) or TMX (Vav1-Myo1f).(H) Heatmap representation showing differential expression of genes associated with T helper cell differentiation in CD4+ T cells from Vav1WT/co-Vav1-Myo1f;CD4-T2 CreER mice treated in vivo with vehicle (WT) or TMX (Vav-Myo1f). Transcription factors implicated in T helper cell fate are marked in red. Gene list was curated from public transcriptome and gene ontology datasets.(I) Graph representation of GSEA –log FDR q values for Th2, Tfh, and Th1 signatures.(J) GSEA showing the enrichment of a Th2 signature associated with the presence of the Vav1-Myo1f fusion, and heatmap representation of the top-ranking genes in the leading edge.(K) Analysis of IL-4 and IFNG secretion by wild-type (WT) or Vav1-Myo1f-expressing CD4+ T cells isolated from Vav1WT/co-Vav1-Myo1f;CD4CreERT2 mice and treated in vitro with vehicle (WT) or 4-hydroxytamoxifen (Vav1-Myo1f).(L) Representative histograms and associated quantification of the transcription factor MAF in CD4+ T cells isolated from Vav1WT/co-Vav1-Myo1f;CD4CreERT2 mice and treated as described in (K).For gene expression analysis, three independent replicates per genotype were analyzed. For in vivo experiments (A–G), the data correspond to two independent experiments (n = 3 animals/group). p values were calculated using a two-tailed Student’s t test. Error bars denote mean ± SD. See also Figure S1.