Figure 3. Kinetic of the specific humoral responses elicited after administration of adjuvant-free Omp19.

BALB/c mice were immunized i.g. (A) or i.p. (B) with L-Omp19 (•) or U-Omp19 (○) without adjuvants as indicated in materials and methods and the kinetic of the Omp19 specific humoral response elicited after immunizations was determined. Serum samples were obtained at the indicated time after the first immunization. Omp19-specific IgG Ab titers were determined by ELISA. Each point represents the mean ± S.E.M of the Ab titer from 5 mice per group. (★) and (★ ★) significantly different from the U-Omp19 immunized group, (P<0.05) and (P<0.01), respectively. This experiment was conducted three times with similar results.