Which statement about IL-5 is NOT true?

Which statement about IL-5 is NOT true?

• A. Inhibits eosinophil growth
• B. Induces growth and differentiation of eosinophils
• C. Promotes differentiation of B cells
• D. Enhances class switching to IgA

Answer: (A)

IL-5’s main role is to stimulate eosinophil development and function. It acts on eosinophil precursors in the bone marrow to promote their growth and maturation, leading to increased eosinophil numbers and activated eosinophils in tissues, especially in allergic responses and parasitic infections. Because of this, the statement that IL-5 inhibits eosinophil growth is not true; IL-5 actually drives eosinophil proliferation and differentiation. The other statements fit with IL-5’s actions: it supports growth and differentiation of eosinophils; it can influence B cells to promote their growth and differentiation; and it can enhance IgA production, reflecting its broader role in humoral responses.

IL-5’s main role is to stimulate eosinophil development and function. It acts on eosinophil precursors in the bone marrow to promote their growth and maturation, leading to increased eosinophil numbers and activated eosinophils in tissues, especially in allergic responses and parasitic infections. Because of this, the statement that IL-5 inhibits eosinophil growth is not true; IL-5 actually drives eosinophil proliferation and differentiation.

The other statements fit with IL-5’s actions: it supports growth and differentiation of eosinophils; it can influence B cells to promote their growth and differentiation; and it can enhance IgA production, reflecting its broader role in humoral responses.