FIG. 5.

Enhanced CTL activity in Cbl-b^−/− mice with acute or chronic infection. Cbl-b^−/− (▴) or B6 (•) mice were infected with 10² (A) or 2 × 10⁶ (B) PFU of LCMV Docile and lymphocytes isolated from tissues at the indicated times. Direct ex vivo CTL activity was measured on virus-infected MC57G targets at an E:T ratio of 100:1 to 1:1 and for an incubation period of 5 or 18 h (t) as indicated. The E:T cell values shown are corrected for the number of D^b/GP1_33-41 and D^b/NP_396-404 tetramer-positive cells in the total virus-specific CTL population. Lysis of untreated target cells was usually ≤10% (5-h assay) or ≤20% (18-h assay) at the highest E:T ratio. However, in certain cases, nonspecific lysis exceeding the 10% or 20% levels was subtracted from corresponding lysis values. Results are representative of two separate experiments.