Human body is constantly contacted and influenced by pathogens or internal danger. When pathogenic infection or dangerous conditions become persistent, inflammatory cells create a microenvironment for the differentiation of naïve T cells (T0 cells) into TH1, TH2, TH17 or Treg cells. Even with the extensive knowledge on TH subsets at a cellular level, the absence of novel markers specific to each T cell subset limits the translation of the knowledge into the clinical stage. In combination with functional gene network analysis, next generation sequencing and gene expression profiling of TH1, TH1, TH17, Treg cells together with naive T cell leads to identification of T cell subset-specific biomarkers. With such method, we can identify new novel receptor of regulatory T cell. Also , identification of the putative ligand for the receptor protein encoded by the candidate gene using IgG fusion protein between Fc portion of IgG and extracellular domain of the receptor which is made in CHO cell system was perfomed. By characterizing the functions of TH subset-specific biomarker candidate genes in vitro and in vivo, we will attempt to provide novel insight into the still largely unknown CD4+ T cell biology and to develop therapeutic and diagnostic remedy for the treatment of inflammation and autoimmunity