Thymosin beta 4 enhances NK cell cytotoxicity mediated by ICAM-1

Thymosin beta 4 (Tβ4), which is the major G-actin sequestering protein, has been shown to have ubiquitous distribution and multiple biological activities. However, Tβ4's functions in relation to natural killer (NK) cells are still unknown. In this study, we show that synthetic Tβ4 peptide increases NK cell cytotoxicity mediated by intercellular adhesion molecule-1 (ICAM-1) through the secretion of cytolytic granules to target cells. This suggests that Tβ4 is a key activator of NK cell cytotoxicity.