Figure 4.

Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) blockade enhances cytokine production during the inductive phase of oral tolerance. BALB/c mice were treated as described in the legend to Fig. 1b. Three days after the last feeding, mesenteric lymph node cells were isolated and cultured with or without 10 µg/ml of ovalbumin (OVA) 323–339 peptide. Culture supernatants were collected 40 hr later and cytokine concentrations were determined by enzyme-linked immunosorbent assay (ELISA). For cultures stimulated with OVA, the differences between the OVA/anti-CTLA-4 group and all other groups are statistically significant (P < 0·05). Results shown are representative of three separate experiments.