T-cell cytokine production is heightened in Ctx⁻ mice after LCMV-WE infection despite similar concurrent viral burdens. (A) Serum IFN-γ levels were assessed in WT and various Ctx⁻ mice at the indicated times after infection with LCMV-WE, a strain of virus that is acutely cleared in WT mice. CD8 depletion eliminated > 90% of serum IFN-γ in prf^−/− mice (n = 8-57/curve). All data are displayed as means ± SEM. Serum IFN-γ levels at days 6 and 8 were significantly different (P < .01) between WT and all Ctx⁻ mice. (B) Virus was quantitated by plaque assay in the spleens of LCMV-WE infected animals at the indicated times. Before day 10, no significant difference (P > .05) was observed between WT and prf^−/− animals (n = 6-8/point). Dashed line indicates limit of detection of the assay.