Different behaviour of thymus in hosts bearing skin homografts or ehrlich ascites carcinoma

Thymus behaviour in A2G male mice transplanted with skin homografts or Ehrlich ascites carcinoma was followed for a period of 28 days. In comparison with control mice of the same strain in which only a slowly physiological involution of the thymus was observed, a marked, irreversible involution was seen in the tumour-bearing mice in contrast with the transient, completely recovered involution in animals transplanted with skin homografts. Thymus behaviour appears as the major structural difference between a host developping a strongly efficient or an inefficient immune response.