Adoptive transfer experiments for identification of negative regulatory cells in tolerized CBA mice.

(A) Six million cells from spleens of naive or tolerant CBA mice were injected into each naive CBA mouse. (B) Five million CD4⁺ T cells were injected into each naive CBA. Control, naive CBA mice with no transfer of spleen cells. Types of spleen cells used for injection are shown at the bottom. There were 4 mice in each treatment group. Each value represents the mean ± SD. Analysis of variance showed that only the mice treated with tolerant T cells (**, panel A) (P ≤ .0001) or tolerant CD4⁺ T cells (**, panel B) (P ≤ .0023) were significantly different from the remaining groups. There were no statistical differences among groups marked with asterisks.