Memory CD4/CD80^acq T cells exhibit CTL activity through the perforin pathway. (A) Memory CD4/CD80^acq T cells were used in a redirected killing assay in the presence (▴) or absence (▪) of concanamycin A (CMA). E/T indicates effector–T-cell ratio. (B) Memory CD4/CD80^acq T cells were labeled with ¹¹¹In and cultured in the absence or presence of 5% dextran (2 × 10⁵ cells/well) for 4 hours. Supernatants were harvested and counted for ¹¹¹In release. Data are representative of 2 repeats. Values are average of 3 wells with SE (standard error of mean).