Which cell seen in the peripheral blood has the function of responding during allergic reactions and antiparasitic reactions? Group of answer choices eosinophil neutrophil lymphocyte basophil
The correct answer and explanation is:
The correct answer is eosinophil.
Explanation:
Eosinophils are a type of white blood cell (leukocyte) found in the peripheral blood that play a crucial role in the body’s immune response, particularly in allergic reactions and defense against parasitic infections.
Role in Allergic Reactions:
- Eosinophils become activated during allergic responses, such as asthma or hay fever.
- They contain granules filled with toxic proteins (e.g., major basic protein, eosinophil peroxidase) that can be released to combat allergens.
- When allergens trigger an immune response, eosinophils migrate from the blood into the tissues, especially at sites of allergic inflammation.
- They modulate inflammation by releasing cytokines and other signaling molecules that influence other immune cells like mast cells and basophils.
Role in Antiparasitic Reactions:
- Eosinophils are particularly effective against multicellular parasites, such as helminths (worms).
- Parasites are often too large for phagocytosis, so eosinophils attack them by releasing cytotoxic granules directly onto the parasite’s surface.
- This degranulation damages or kills the parasite, helping to clear the infection.
Why Not Other Cells?
- Neutrophils: These are the most abundant white blood cells and are the first responders to bacterial infections. They kill pathogens mainly by phagocytosis and release of enzymes, but they are not specialized for allergic or parasitic reactions.
- Lymphocytes: This group includes B cells, T cells, and natural killer (NK) cells. Lymphocytes are essential for adaptive immunity, including antibody production and targeted killing of infected cells, but they are not the primary responders in allergy or parasitic defense.
- Basophils: These cells also play a role in allergic reactions by releasing histamine and other mediators that cause inflammation and bronchoconstriction. However, they are not primarily involved in antiparasitic defense.
Summary
- Eosinophils are key players in allergic and antiparasitic immune responses.
- They respond by releasing toxic granules that help neutralize allergens and kill parasites.
- Their presence and activation are critical in conditions like asthma, allergies, and parasitic infections.
This functional specialization distinguishes eosinophils from other white blood cells seen in peripheral blood.