American Board of Surgery Qualifying Exam (ABS QE) Practice Test

Which interleukin is primarily responsible for PMN chemotaxis?

1. IL-6

2. IL-8

3. IL-10

4. INF

The correct answer is: IL-8

Interleukin-8 (IL-8) is primarily responsible for the chemotaxis of polymorphonuclear leukocytes (PMNs), commonly known as neutrophils. It acts by binding to specific receptors on the surface of these cells, leading to their migration towards the site of infection or inflammation. This chemotactic property is crucial in the immune response, where neutrophils play a key role in defending the body against microbial invasion. IL-8 is produced by various cell types, including macrophages and epithelial cells, in response to pro-inflammatory stimuli. Once released, it effectively attracts neutrophils to areas needing an immune response, facilitating rapid recruitment of these vital immune cells. Understanding the role of IL-8 in chemotaxis helps illustrate its importance in inflammation and innate immunity, distinguishing it from other interleukins. For example, IL-6 is more associated with systemic inflammatory responses and the activation of T-cells, while IL-10 is an anti-inflammatory cytokine that limits immune responses. Interferons (INF) play various roles in the immune system but are not primarily involved in the chemotaxis of neutrophils. Recognizing the specialized function of IL-8 enhances comprehension of the intricate signaling pathways