LIGHT-deficiency impairs CD8+ T cell expansion, but not effector function.

LIGHT, a newly identified member of the tumor necrosis factor (TNF) family, is expressed on activated T lymphocytes. To evaluate how LIGHT contributes to T cell functions, we generated LIGHT-deficient (LIGHT(-/-)) mice using gene targeting. Disruption of LIGHT significantly reduced CD8(+) T cell-cycle progression, leading to reduced proliferation to anti-CD3, anti-CD3/anti-CD28 or allogeneic stimulation, whereas proliferation of CD4(+) T cells remained unchanged.