Galectin-9 (LGALS9)

Has high affinity for the Forssman pentasaccharide (PubMed:18005988). Binding to HAVCR2 induces T-helper type 1 lymphocyte (Th1) death (PubMed:16286920).

Also stimulates bactericidal activity in infected macrophages by inducing macrophage activation and IL1B secretion which restricts intracellular bacterial growth (By similarity). Ligand for P4HB; the interaction retains P4HB at the cell surface of Th2 T-helper cells, raising disulfide reductase activity at the plasma membrane, altering the plasma membrane redox state and improving cell regeneration (PubMed:21670307).