Abrogation of oral tolerance by feeding encapsulated antigen

Results from previous studies have indicated that suppression of immune res ponses cannot be abrogated once oral tolerance has been established. Using a new methodology, OVA was encapsulated and fed to tolerized BDF1 mice. Res ults from these studies indicated that although IgG2a titers remained low, total IgG and IgG1 antibody titers were no longer suppressed compared to co ntrols. Furthermore, in vitro splenocyte proliferation was not significantl y suppressed in tolerized mice fed encapsulated OVA To determine whether or al tolerance could be abrogated in other strains of mice, BALB/c mice were tolerized and fed encapsulated OVA Results from these studies indicated tha t IgG2a as well as IgG1 and total anti-OVA antibody titers were no longer s uppressed. Although splenocyte proliferation did remain significantly suppr essed in these mice, IFN-gamma and IL-4 levels were no longer decreased. To the best of our knowledge, this is the first time that abrogation of an es tablished oral tolerance has been demonstrated. (C) 2000 Academic Press.