Question

If an individual failed to develop a thymus because of a genetic defect, what would happen to humoral and cell-mediated immunity?

Answer 1

• The thymus is essential for the maturation and differentiation of T-lymphocytes (T-cells). Without a thymus, immature lymphocytes cannot differentiate into mature T-cells.
• Cytotoxic T-cells, which are responsible for cell-mediated immunity by directly destroying infected or abnormal cells, would be absent or deficient. This impairs cell-mediated immunity.
• Helper T-cells, which play a crucial role in activating both cell-mediated and humoral immune responses (including stimulating B-cells to produce antibodies), would also be absent or deficient. Their absence would thus impair humoral immunity as well.