Abstract
Goat hearts were transplanted to the thorax of 54 calves that had received either no treatment or had been immunosuppressed with antilymphocyte serum and prednisolone, separately and together. Sheep and goat skin was also transplanted to 17 calves, some of which were immunosuppressed. The hearts in treated calves beat for up to 40 days whereas in untreated calves they were rejected in 4-6 days. Similar results were obtained with the skin transplants, which survived up to 79 days in treated calves. In rejected hearts from immunosuppressed calves, the cellular response was mainly eosinophilic and neutrophilic, but in untreated calves it was lymphoreticular. In rejected skin in treated and untreated calves, the response was lymphoreticular and neutrophilic. Neither antilymphocyte serum nor prednisolone alone could prevent rejection of hearts, but in combination they were very effective.