Combined immunodeficiency is a condition in which the animal fails to produce functioning which cells?

Combined immunodeficiency is a condition in which the animal fails to produce functioning which cells?

• A. Plasma cells
• B. B cells
• C. T cells
• D. B and T cells

Answer: (D)

Combined immunodeficiency shows up when the adaptive immune system’s two arms are both defective: B lymphocytes (humoral immunity) and T lymphocytes (cell-mediated immunity). When B cells don’t function, antibody production drops and plasma cells—these antibody-secreting descendants of B cells—are affected as a result. At the same time, T cells fail to develop or work properly, so cellular immunity is compromised. The lack of functional B and T cells leaves the animal highly vulnerable to a wide range of infections because there’s no coordinated antibody response and no proper cellular defense. So the defining feature is the failure of both B and T cells to function, which is why the answer includes both.

Combined immunodeficiency shows up when the adaptive immune system’s two arms are both defective: B lymphocytes (humoral immunity) and T lymphocytes (cell-mediated immunity). When B cells don’t function, antibody production drops and plasma cells—these antibody-secreting descendants of B cells—are affected as a result. At the same time, T cells fail to develop or work properly, so cellular immunity is compromised. The lack of functional B and T cells leaves the animal highly vulnerable to a wide range of infections because there’s no coordinated antibody response and no proper cellular defense. So the defining feature is the failure of both B and T cells to function, which is why the answer includes both.