Abstract
The effect of passively administered IgG1 and IgG2 anticarrier antibodies on the IgG1 and IgG2 antihapten response has been studied. Guinea pigs were immunized with dinitrophenylated bovine gamma globulin mixed with purified IgG1 or IgG2 antihuman gamma globulin antibodies, i.e., antibodies directed against a limited range of the carrier determinants. Humoral IgG1 and IgG2 anti-DNP antibody contents were assayed at weekly intervals and 4 to 10 days after a booster injection of antigen in saline given on the 12th wk. The main finding was the sustained suppressive effect of passive IgG1 anti-carrier antibodies on the active IgG1 antihapten response. This result is compared with the enhancing effect of passive IgG1 antihapten antibodies and is discussed in the light of T cell-B cell and hapten-carrier relationships, leading to the proposal of a regulatory function of the Fc portion of the IgG1 anticarrier antibody, combined with the antigen, on the T cell.