Which leukocyte is primarily involved in allergic reactions and responds to parasitic infections?

Eosinophils are specialized white blood cells that play a crucial role in the body's immune response, particularly during allergic reactions and parasitic infections. They are characterized by their ability to detect and respond to pathogens like helminths (worms) and certain types of allergens.

When the body encounters these triggers, eosinophils become activated and release cytotoxic granules filled with enzymes and toxic proteins that target and destroy these invaders. This is key in combating parasitic infections, as eosinophils can damage and kill multicellular parasites through mechanisms such as degranulation, where they release their stored chemicals to exert an effect on the pathogens.

Furthermore, eosinophils are implicated in the inflammatory response associated with allergic reactions, where they can contribute to the symptoms of asthma, hay fever, and other hypersensitivity reactions. Their presence in tissues affected by allergies is a hallmark of these immune responses, marking them as vital players in both allergy and parasitic disease contexts.