title: Galectin-9 regulates T helper cell function independently of Tim-3.
abstract: β-Galactoside-binding lectin 9 (galectin-9) is a tandem repeat-type member of the galectin family. It was initially characterized as an eosinophil chemoattractant and an inducer of apoptosis in thymocytes. Subsequently, galectin-9 was identified as a ligand for transmembrane immunoglobulin mucin domain 3 (Tim-3), a type I glycoprotein induced on T cells during chronic inflammation. Work in autoimmune diseases and chronic viral infections have led to the current hypothesis that the function of Tim-3 is to limit immune responses. However, it is still not known to what degree these effects are due to the galectin-9/Tim-3 interaction. In this study, we show that galectin-9 is not limited to the role of a pro-apoptotic agent, but that it can also induce the production of pro-inflammatory cytokines from T helper cells. This effect is dose-dependent and does not require Tim-3. These findings suggest that the effects of galectin-9 on T cells are more complex than previously thought and are mediated by additional receptors apart from Tim-3.
authors.affiliation: Department of Immunology, University of Pittsburgh School of Medicine, BST E-1056, Pittsburgh, PA 15261, USA.
authors.forename: Ee W
authors.initials: EW
authors.lastname: Su
authors.forename: Shuguang
authors.initials: S
authors.lastname: Bi
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: Kane
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D037161:Galectins / Q000378:metabolism*; D000072597:Hepatitis A Virus Cellular Receptor 2; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011991:Receptors, Virus / Q000235:genetics / Q000378:metabolism*; D006377:T-Lymphocytes, Helper-Inducer / Q000502:physiology*
chemical_list: D016207:Cytokines; D037161:Galectins; C442241:Havcr2 protein, mouse; D000072597:Hepatitis A Virus Cellular Receptor 2; C105032:LGALS9 protein, human; D011991:Receptors, Virus