Th9 Cells

Etienne Humblin, François Ghiringhelli, Frédérique Végran

Ritobrata Goswami

CD4+ T cells are key components of the immune system that shape the anticancer immune response in animal models and in humans among other responses. The biology of CD4+ T cells is complex because naïve CD4+ T cells can differentiate into various subpopulations with various functions that depend on the milieu. Recently, a new population of IL-9-secreting T cells called Th9 cells has been described. These cells are characterized by their ability to produce IL-9. These cells were described to be involved in parasite infections and allergic inflammation. However, some reports described their presence in the tumor bed in mice and humans. Molecular events that account for Th9 effector properties and differentiation are still elusive. To study these mechanisms, downregulation of gene expression and protein-DNA interaction detection allow to identify and study putative transcription factors regulating gene expression during their differentiation. Here, we describe three methods allowing the study of transcription factors in Th9 cells: siRNA transfection for downregulation of gene expression, and chromatin immunoprecipitation and liquid luminescent DNA precipitation assay to detect protein-DNA interactions.