The WBA simulates IFN-α induction by CpG-ODN in vivo more accurately than the PBMC assay.

a – PBMC were stimulated with B-type (CpG 2006) and C-type (M362) CpG-oligonucleotides as indicated. C20-DNA served as a negative control (neg contr). After 48 h induction of IFN-α was analyzed using ELISA. b – Done as described for (a) but whole blood anticoagulated with Heparin, EDTA or Hirudin was used. c – Complete whole blood or whole blood in which plasma was replaced by medium or medium+albumin was anticoagulated with Hirudin and stimulated with B-type (CpG 2006) and C-type (CpG M362) CpG-oligonucleotides or C20-DNA (neg contr) as indicated. After 48 h supernatant was analyzed for IFN-α concentration. Graph shows percentage of induced IFN-α compared to CpG M362 (induced IFN-α concentrations: 1 µg/ml CpG M362: 1697 pg/ml; 5 µg/ml CpG M362: 3627 pg/ml). Results of at least six donors are shown as mean +/− SD in (a–c).