CD28 and neoplasm: We sorted naïve CD8+ T cells from the spleens of wild-type mice, stimulated them with a CD28 antibody and gradient concentrations of a CD3 antibody for 72 h to mimic the stimulation of the T-cell receptor (TCR) by tumour antigens, and detected Rig-I expression using Western blotting to investigate the upregulation of Rig-I induced by the activation of T cells.