LCMVClone13 infection induced anergy induced in CD8 T cells is reversed by anti-IL-10 treatment. a) Splenocytes from LCMVARM immune (dashed line), LCMVClone13-infected with (closed square) or without (open square) anti-IL-10 (day 30 p.i.), were stimulated in vitro for 5 days with LCMV GP33 peptide and IL-2, and their capacity to lyse LCMV GP33 peptide-pulsed targets was measured by 51Cr release assay. The effector to target ratio was calculated based on CD8 frequency. There were 5–7 mice per group, each line represents one mouse. Background killing in unpulsed target cells was less than 10%. b) The amount of anti-LCMV IgG, 30 day p.i., in the sera of naïve (filled squares), LCMVClone13 infected with (filled triangles) and without anti IL-10 treatment (filled circles) was measured by ELISA. The difference in anti-viral IgG between the LCMVClone13-infected mice receiving anti-IL-10 versus untreated is statistically significant (p = 0.002).