Which of the following substances is a secretory product of helper T-Cells?

• A. Interleukin 2
• B. Interleukin 1
• C. Haptens
• D. Allergens

Answer: (A)

The main idea here is that helper T cells release signaling proteins called cytokines to coordinate the immune response. Interleukin-2 is a cytokine produced by activated helper T cells and serves as a growth factor that drives the proliferation and activation of T cells (and can influence B cells as well). This autocrine/paracrine signaling is essential for clonal expansion of the T-cell population after antigen recognition, helping build a stronger adaptive response.

Interleukin-1, on the other hand, is primarily produced by macrophages and other innate immune cells as part of inflammation, not by helper T cells. Haptens are small molecules that become antigenic when bound to a protein, and allergens are substances that trigger allergic reactions; neither are secreted by helper T cells. Thus, interleukin-2 is the secretory product best matching helper T cells.