Demonstration of a cellular defect in the thymus of hereditary muscular dystrophic chickens.

The thymuses of different aged hereditary muscular-dystrophic (MD) chickens were examined for abnormalities. Histochemical analyses showed a normal cellular profile. Thymic myoid cells were normal as to numbers, size, distribution, and metabolic status. The thymuses of MD chickens, however, exhibited two abnormalities not found in age and sex-matched normal controls. The thymus lobes were smaller in size and weighed less than the thymus lobes from controls, and the thymus cells from MD chickens gave reduced Con A and elevated PHA-T-cell mitogen-mediated blastogenic responses.