Specific Suppression of MLC and CML by Anti‐Idiotypic Antibodies in the Mouse

Abstract

Rabbit antisera directed against idiotypic determinants of alloreactive mouse CBA anti-C57BL/6 T [thymus-derived] blasts were raised as described below. A rabbit serum directed against nonspecific CBA blasts cells was prepared by injecting CBA concanavalin A blasts 3 times at monthly intervals into a rabbit. Specific CBA anti-C57BL/6 T lymphoblasts were induced in a mixed lymphocyte culture (MLC), were purified by gravity sedimentation through a fetal calf serum gradient, and, finally, were incubated with the anti-blast serum from the first step. During this incubation, presumably all epitopes of the blast cell population were blocked by anti-blast antibodies, except for the greatly amplified set of CBA anti-C57BL/6 alloreactive idiotypes. The mixture was then injected into fresh rabbits, which were boosted with similar mixtures after 3 and 6 wk. Blood samples were removed 10 days after each injection. Such sera, when used together with complement, specifically inhibted the stimulation of CBA cells by C57BL/6 antigens in MLC and the CBA anti-C57BL/6 killer cells.