Tolerance Induction to H‐2 Central Region Target Antigens: In Vivo/in Vitro Correlations

Tolerance was induced against cytotoxic target determinants coded for by genes of the I region. Neonatal recipients were immunized with high doses of cells from an I region incompatible donor. Nonreactivity in adult life did not reflect extensive donor cell chimerism, since the great majority of cells in spleens of animals rendered tolerant were of host phenotype. Although specific nonresponsiveness in CML could be induced by these protocols, the MLC proliferative response was in most cases still present alghough very much decreased. In only a very occasional animal was complete nonreactivity in MLC seen. The nonresponse in CML was paralleled by acceptance of thyroid allografts as measured by radioactive iodine incorporation and morphological studies.