peripheral lymphoid tissues of mice which have been thymectomized at 2 or 4 weeks of age , that is , before they achieve adult body weight , have been shown to be lacking in cells responsive to the t-cell mitogen , phytohaemagglutinin , when the animals became adult , and these mice have also been shown to have a deficient immune response against sheep erythrocytes .
C0021756
t-cell mitogen
C0301872
immune response