In Vitro Reactivity in Allograft Tolerance: Persistence of Mixed Leukocyte Culture Reactivity in Highly Tolerant Rats

Mixed leukocyte culture reactivity was studied in adult W/Fu rats judged to be highly tolerant after the inoculation of (W/Fu × BN)F1 hybrid spleen and bone marrow cells at birth. Reactivity was observed in a majority of tolerant donors tested and documented by quantitative dose-response and kinetic studies. Allograft tolerance cannot be explained by a complete lack of specific immune reactivity to tolerated alloantigens.