Fig. 4.

Knockdown of MS4a4B by shRNA vector enhanced anti-CD3-induced caspase activities. a shMS4a4B-vector (or control shLuc vector)-infected T32 cells were pre-activated by αCD3/αCD28 stimulation, and then were primed with αCD3 antibody alone. Cells were harvested from culture at 24 h of αCD3 stimulation for analyzing activation of caspases by Caspase-Glo@-Assays. Data were presented as mean ± SD of relative light units from duplicate. **p < 0.01. One of two independent experiments is shown. b Primary CD4⁺ T cells were isolated from C57BL/6 mice. Isolated cells were activated for 36 h with αCD3/αCD28 antibodies and then were transfected with siLuc or siMS4a4B. Cells were harvested at 24 h from culture. MS4a4B protein level was determined by intracellular flow cytometry with anti-MS4a4B antibody staining. Grey peak: isotype control; solid line: anti-MS4a4B antibody. c Harvested cells as described in “b” were re-stimulated with αCD3 antibody alone (5 μg/ml) for an additional 24 h and then were lysed with cell lysis buffer. β-Actin control and pro- and cleaved caspases 3, 8 and 9 were detected by western blotting with corresponding antibodies. A representative of three experiments is shown