Final answer:
Healthy adults typically have eosinophils making up 2-4 percent of the total white blood cell count, playing crucial roles in immune response and combating parasites and allergies.
Step-by-step explanation:
In healthy adults, eosinophils should constitute about 2-4 percent of the total leukocyte count. These cells are usually between 10-12 µm in diameter. Eosinophils are characterized by their granules that stain effectively with an acidic stain known as eosin, giving the granules a distinctive red to orange color. The nucleus of an eosinophil typically has two to three lobes.
Eosinophils play a vital role in the immune response, especially involving allergies, parasitic worm infestations, and some autoimmune diseases. They contain granules loaded with antihistamine molecules to counteract inflammatory chemicals like histamines, and some granules even have molecules toxic to parasites. Besides, these cells are capable of phagocytosis, effectively engulfs and destroys pathogens, especially when combined with antibodies in an antigen-antibody complex. It is important to note that a high eosinophil count might indicate allergies or parasitic infections, while a low count could point to drug toxicity or stress.