Interleukin-5 (IL-5) is a cytokine produced by Th2 Cells. IL-5 stimulates proliferation of eosinophils, which are important in the immune response against parasitic worms, as well as in diseases like allergic asthma. In addition, IL-5 acts on B-cells to promote their growth and class switching to Immunoglobulin A (IgA). This increase in IgA production provides immunity at mucosal surfaces.

Key Points

  • Interleukin-5 (IL-5)
    • Secreted by Th2 cells
      • Also produced by mast cells, to a lesser extent
    • Stimulates growth and differentiation of eosinophils
      • Important in defense against parasitic infections
      • Involved in pathogenesis of allergic diseases
    • Enhances B cell growth and class switching to Immunoglobulin A (IgA)
      • Important for immunity at mucosal membranes