FIG. 4.

Determination of CFA/I-induced IFN-γ production and CD4 cell activation dependence in mice immunized with S. enterica serovar Dublin FlaII. IFN-γ production was measured in supernatants of splenocyte cultures derived from BALB/c mice immunized via the i.p. (gray bars) or p.o. (black bars) route with S. enterica serovar Dublin FlaII. Splenocyte cultures were kept in RPMI medium or stimulated with 25 μg of purified CFA/I fimbriae/ml. Cultures were further treated with neutralizing MAb GK 1.5 (anti-CD4), TIB105 (anti-CD8), or both (anti-CD4 + anti-CD8). Control cultures were treated with the anti-β-galactosidase GL 117 MAb (control antibody). Data from a representative experiment are expressed as means ± SEM of duplicate cultures.