To investigate the regulation of pathogenic Th2 (pTh2) cells and the role of histone deacetylase 1 (HDAC1) in the respective processes, we used a new in vitro protocol for generating pTh2 cells and performed qunatitative mass spectrometry analysis based on TMTpro 16plex multiplexing to analyze proteomes. We profiled classical Th2 and pTh2 cells from wild type (WT) mice and mice with a T cell-specific deletion of HDAC1 (HDAC1-cKO).