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- Title
Oral Tolerization Leads to Active Suppression and Bystander Tolerance in Adult Rats while Anergy Dominates in Young Rats.
- Authors
Lundin, B. S.; Dahlgren, U. I. H.; Hanson, L. Å.; Telemo, E.
- Abstract
Oral tolerance was induced in 4-week-old (young) and 12-week-old (adult) rats by feeding oval-bumin (OvA)-containing pellets during 4 weeks. Seven weeks after removal of the OvA-pellets the rats were immunized with a mixture of OvA and human serum albumin (HSA) in Freund's complete adjuvant (FCA), and the following immune response was monitored. Both the young and adult groups of OvA-fed rats had significantly stippressed OvA-specific delayed-type hypersensitivity (DTH) responses and T-cell proliferation, reflecting a long-lasting T-cell tolerance to OvA both <em>in vivo</em> and <em>in vitro</em>. Furthermore, spleen cells from rats tolerized as adults were able to suppress the proliferation of primed T-cells from normal immunized rats, demonstrating the presence of antigen-specific suppressive cells. Accordingly, the adult rats showed bystander suppression of the response to HSA with respect to DTH-reaction, specific proliferation, and reduced enlargement of the draining lymph nodes after immunization. There was no evidence of active suppression in vitro or bystander tolerance in the orally tolerized young group, indicating that anergy rather than active suppression was prevalent in these rats. Furthermore, in the young group there was no suppression of the antibody response since the IgG and IgE anti-OvA antibody levels were indistinguishable from those of the controls. Contrary to the young rats, the adult fed group showed transiently elevated levels of IgG anti-OvA antibodies at 1 week post-immunization, followed by a .subsequent significantly suppressed IgG antibody response. In conclusion, the results demonstrate that the induction of anergy or active suppression after antigen feeding can be determined by the age at which the antigen is introduced to the mucosal immune system.
- Subjects
BLOOD plasma; MURIDAE; ALBUMINS; SERUM albumin; IMMUNOLOGICAL adjuvants; RATS; IMMUNE response
- Publication
Scandinavian Journal of Immunology, 1996, Vol 43, Issue 1, p56
- ISSN
0300-9475
- Publication type
Article
- DOI
10.1046/j.1365-3083.1996.d01-15.x