FIG. 4.

Effects of IFN-γ on FV-induced immunosuppression. Anti-SRBC antibody titers at 28 days post FV challenge were determined for resistant H-2^a/b (A.BY × B10.A)F₁ mice in which IFN-γ was neutralized by intraperitoneal injections of rat MAb XMG1.2 for 3 weeks as previously described (19). The difference between the log₂ geometric mean titers of infected, rat immunoglobulin G-treated control mice (5.6) versus infected, anti-IFNγ-treated mice (2.6) was statistically significant by the unpaired t test (P < 0.0001).