Immunosuppressive Effect of Serum from CBA Mice Made Tolerant by the Supernatant from Ultracentrifuged Bovine γ Globulin

In studies on tolerance to bovine γ globulin (BGG) induced in CBA mice by injection of the supernatant fraction of ultracentrifuged BGG, tolerance was not terminated by adoptive transfer of 108 spleen cells from normal or immune mice. Moreover, the serum of tolerant mice passively transferred to normal mice inhibited the immune response to BGG. This inhibition was attribute 1 to the presence of specific antibody in the serum of tolerant mice.