Inhibition of specific immune responses by feeding protein antigens. III. Evidence against maintenance of tolerance to ovalbumin by orally induced antibodies
Hanson, D.G.; Vaz, N.M.; Maia, L.C.; Lynch, J.M.
Journal of Immunology 123(5): 2337-2343
1979
ISSN/ISBN: 0022-1767 PMID: 114587 Document Number: 149214
Single and multiple intragastric feedings of ovalbumin (OVA) to high-responder BDF1 mice resulted in virtually complete unresponsiveness to later parenteral immunization with OVA in A1(OH)3 adjuvant as indicated by antibody titers in Farr assays and in passive cutaneous anaphylaxis (PCA) assays for IgE antibodies. Repeated feedings of partially tolerizing doses of antigen had a cumulative inhibitory effect on subsequent responsiveness. Slight increases in primary antigen binding were detected in the serum of antigen-fed mice not given parenteral immunization, although rates of clearance of radiolabeled OVA from the blood were similar in normal and tolerant animals. Serum recovered from tolerant mice 7 or 14 days after feeding did not inhibit antibody responses of normal recipients. Responsiveness of normal or OVA-primed syngeneic spleen cells was substantially reduced upon transfer into recipients that were previously fed OVA when compared with transfer into saline-fed recipients. The differences in responsiveness of lymphocytes transferred into OVA- and saline-fed mice were completely eliminated by irradiation (850 R) of the recipient animals at 7 or 20 days after feeding and immediately before the transfer. Apparently tolerance after ingestion of OVA is actively maintained but this tolerance is not mediated by orally induced antibodies or serum factors that were associated with unresponsiveness to ingested antigens in similar experimental systems.