FIG. 3.

Influence of OM-85 on primary and secondary IgG1 antibody responses of newborn rat pups immunized with soluble antigen. Administration of OM-85 or placebo (400 μg per g of body weight) to newborn rat pups and 12-week-old adult rats commenced on the same day as i.p. immunization with soluble OVA (25 and 100 μg, respectively). Dose administration was continued for 14 consecutive days, and serum was collected for the measurement of OVA-specific IgG1 and IgG2b primary antibody response titers (A). Administration of OM-85 or placebo was continued every second day until day 28, when treatment was withdrawn and each rat received a challenge dose of 100 μg of OVA in PBS i.p. After another 14 days, sera were collected and secondary antibody response titers were measured by ELISA (B). The data are representative of three separate experiments, and each bar represents the group mean (n = 5 to 9 rats). Mann-Whitney U test-generated P values indicate a significant difference in peripheral antibody response due to administration of OM-85 (∗, 0.05 > P > 0.01; ∗∗, 0.01 > P > 0.005; and ∗∗∗, 0.005 > P > 0.0001).