Induction and identification of peripheral tolerance to ovalbumin administered intravenously or orally

【Objective】The study is to establish a model tolerance to ovalbumin.【Mathod】Mice gastrically intubated ovalbumin(OVA) had been divided into experiment group A,B,C,D,E and F and their corresponding control groups.Group A and B were at the dose of 50 or 100 μg every other day for 5 times.The rest were i.v.at the dose of 5,10,50 or 100 μg once for each.The oral administration groups and the intravenously injected groups were challenged with 200 μg OVA,at 7 days or 5 days interval,respectively.15 days later,mice were sacrificed.Lymphocytes responses were assessed by MTT method and antibody were tested by ELISA.And then group C and D injected 5 or 10 μg were exposed to the second and the third immunization.Antibody was detected at 15 days interval for 4 times.【Result】The regimen of OVA oral administration group A and B can induce Ag-specific lymphocytes profound suppression,with simulate index 0.603±0.03 and 0.715±0.08,repectively.And the anti-OVA IgG level was remarkablly affected.As to the intravenous group C and D,these lymphocytes from mice i.v.5 or 10 μg OVA were totally unresponsiveness in all mice tested,with index 0.096±0.01 and 0.083±0.01,respectively while group E and F were normally responded.Antigen-specific B cells were normally responded with the first immunization.But they had no reactivity to repetitious immunization and anti-OVA IgG were gently declined in 2 months.【Conclusion】Low dose of OVA intravenous injection can initiate specific immune tolerance while the oral administration in this experiment can just suppress the responses of T cells and B cells evidently.