Exchange of skin grafts among monozygotic quadruplets in armadillos

Skin grafting experiments, with long-term follow-ups, on three litters of armadillo quadruplets born in our laboratory have confirmed the familiar rule that grafts exchanged between monozygotic littermates are not rejected as a consequence of alloimmune reactions. A possible explanation of the striking discrepancy between the present findings and those of a previous study is uncertainty about the relationships of the previous animals, which were obtained from a commercial dealer at 10 days of age.