Influence of size and gene dosage on the survival of skin allografts on rats rendered tolerant at birth.

The attributes of the test grafts with which putatively tolerant rats are challenged influence their immune response. Lewis (Lew) rats inoculated at birth with Lew/BN F1 hybrid bone marrow cells accept large skin allografts more readily than small allografts, and F1 hybrid skin grafts survive better than BN transplants. The results indicate that the survivals of these major histocompatibility complex-incompatible grafts are determined by the same factors that operate when only weak histoincompatibilities prevail.