Question

Mammals born without a thymus gland fail to manufacture

• A. B - Lymphocytes
• B. T - Lymphocytes
• C. Plasma cells
• D. Basophils

Answer 1

The correct option is B T - Lymphocytes

Removal of the thymus gland in the adult has little effect, but when the thymus is removed in the newborn, T cells in the blood and lymphoid tissue are depleted and failure of the immune system causes a gradual, fatal wasting disease.

The animal whose thymus has been removed at birth is less able to reject foreign tissue grafts or to make antibodies to certain antigens. Moreover, certain parts of the white pulp of the spleen and lymph nodes are much reduced in size. Hence, the T cells produced in the thymus and transported to the lymphoid tissues are crucial elements in the development of immunity.