Microbiology Practice Exam

What role do eosinophils play in the immune system?

1. Allergic reactions

2. Phagocytosis

3. Toxin response to parasites

4. Histamine suppression

The correct answer is: Toxin response to parasites

Eosinophils are a type of white blood cell that play a crucial role in the immune response, particularly in combating parasitic infections and contributing to allergic reactions. They are particularly effective against larger multicellular pathogens, such as helminths (worms), which are too large for phagocytosis. When eosinophils encounter these parasites, they release cytotoxic granules containing various enzymes and proteins, such as major basic protein and eosinophil cationic protein, which can damage the parasite and help eliminate it from the host. In the context of the immune response, eosinophils are also involved in mediating inflammation and tissue repair, and they can enhance the overall immune response. They respond to various signals, including those from other immune cells and the products released by parasites, making them vital in the body's efforts to control and eliminate parasitic infections. While eosinophils do play a role in allergic reactions, their primary function connected to the option chosen lies specifically in the response to parasitic infections. They are less involved in processes such as phagocytosis or histamine suppression compared to other immune cells like macrophages or mast cells. Eosinophils typically mediate the immune response against larger pathogens rather than