Db-SAP tetramers activate and eliminate antigen-specific T cells in vitro. (A) Incubation of a 50:50 mixture of female Vα2+ (P14) and T3.70+ (H-Y) CD8+ T cells with gpC9M-SAP or hyC2A-SAP results in the selective loss of cognate T cells. Tetramer mixtures are indicated by the legends above the dotplots. Following an initial 2-hour incubation with tetramer, cells were washed repeatedly and then cultured for an additional 46 hours prior to harvest and staining. For each group, 104 events were analyzed; the plots show only live (7-AAD−) CD8α-gated cells. Numbers indicate the cell number in the region. (B) Loss of T cells with Db-SAP tetramer treatment is not the result of inadequate stimulation through the TCR. Exposure to gpC9M or gpC9M-SAP causes equivalent changes in CD62L and CD69 expression, and identical increases in ΔΨm (measured as increased DiIC