IMMUNOLOGICAL RESPONSES TO FED PROTEIN ANTIGENS IN MICE .1. REVERSAL OF ORAL TOLERANCE TO OVALBUMIN BY CYCLOPHOSPHAMIDE

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  • 1 January 1982
    • journal article
    • research article
    • Vol. 45  (1) , 105-113
Abstract
Mice were fed 2 mg and 25 mg ovalbumin (OVA) 2 wk before systemic immunization and the resulting humoral antibody and cell-mediated immune (CMI) responses were followed. While 25 mg OVA will reduce subsequent IgM, IgG and CMI responses to OVA, feeding 2 mg OVA will only suppress CMI responses and to a lesser extent the IgM response. The tolerant state induced by feeding 25 mg OVA was only partially prevented by 100 mg/kg cyclophosphamide (CY) while the suppressed CMI after feeding 2 mg OVA was completely blocked by CY pretreatment. The humoral and cell-mediated limbs of the immune response may be controlled by different regulatory systems after feeding antigen, and that activation of these systems is dependent on the dose of oral antigen used. CY pretreatment will allow the development of CMI in the gut and gut-associated lymphoid tissue after oral OVA. This phenomenon is probably related to breakdown of oral tolerance induction.