Virus load after adoptive transfer of virus-specific CD8⁺ T cells. Chronically FV-infected (B10 × A.BY) F1 mice were treated with 4 × 10⁶ naive, virus-specific TCRtg CD8⁺ T cells and 15 nmol of the B-type CpG-ODN (CpG-1668: 5′-tcc atg acg ttc ctg atg ct-3′) (CpG) or control ODN without the CpG motif (5′-tcc atg agc ttc ctg atg ct-3′)¹²  (Control) were injected twice, once on the day of T-cell transfer and again 4 days later. As controls, 1 group of animals received CpG-ODNs without T cells and 1 group of chronically infected mice did not receive any treatment (none). At 1 week (closed symbols) or 3 weeks (open symbols) after transfer, the spleen cells of the recipients were harvested and virus loads were determined in an infectious center assay.⁹  Mean values for each group are indicated by bars. The differences in viral loads between the groups of mice receiving CpG-ODNs or control ODNs together with T cells were statistically significant (unpaired t test).