Cellular events in tolerance. III. Carrier tolerance as a model for T cell unresponsiveness

Lewis rats pretreated with 10 mg of the soluble supernatant of ultracentrifuged sheep γ globulins (ShIgSo) and challenged with trinitrophenylated (TNP) ShIg in adjuvant initially developed significantly fewer anti TNP plaque forming cells than untreated controls. The effect was specific because ShIgSo tolerant rats responded normally to TNP rabbit γ globulin. Carrier tolerance lasted at least 6 months and could be induced with as little as 100 μg ShIgSo. Adoptive transfer experiments to irradiated recipients demonstrated that thymocytes could reverse carrier unresponsiveness. 'Suppressor' cells were not detectable in carrier tolerant spleen populations. The diminution of responsiveness to TNP on a tolerated carrier thus provides a model for the study of T cell unresponsiveness in vivo.