FIG. 4.

The effect of ICN 17261 and ribavirin on the in vitro cytokine (A) and in vivo contact hypersensitivity (B) responses to the contact allergen DNFB. (A) The effect of ICN 17261 and ribavirin on secreted type 1 and type 2 cytokine levels in mouse LNC from individual BALB/c mice sensitized with DNFB (see Materials and Methods). Extracellular levels of type 1 (IL-2 and IFN-γ) and the type 2 cytokine IL-10 were determined in anti-mouse α/β-TCR-activated LNC from seven primed mice following a 48-h incubation in the presence of 0 and 2 μM ribavirin (RIB, top panels) or ICN 17261 (17261, bottom panels). The effect of ribavirin or ICN 17261 on cytokine levels was assessed in cell-free supernatants in duplicate by ELISA analyses and are represented as mean concentration. The data shown are representative of three separate experiments each using data from six mice. (B) CHS responses were induced in three groups of five mice by sensitization and challenge with DNFB as described in Materials and Methods. At the time of challenge with 0.12% DNFB, one group was administered 5 μg of ribavirin (RIB) and a second group was administered 5 μg of ICN 17261 (17261), both given in 50 μl of PBS by i.p. injection. The third DNFB-primed group (Primed) was untreated. The ear swelling in all groups (including an unsensitized control group [Naïve]) was measured after 24 h and was compared to prechallenge values. The data shown as mean ear swelling (Ear Measurement) are representative of four separate experiments with three to five animals in each test group. Error bars indicate SDs. Asterisks indicate P < 0.001 when compared to the primed group.