Final answer:
Major basic protein serves to destroy parasites by disrupting their outer membranes and is also associated with epithelial cell damage in asthma due to its inflammatory properties. It's a significant factor released by eosinophils during immune responses.
Step-by-step explanation:
The function of major basic protein produced by eosinophils includes several roles. First, it destroys parasites, particularly helminths, by attaching to and disrupting their outer membranes. Secondly, this protein contributes to epithelial cell damage in asthma.
This damage occurs because the major basic protein is also involved in inflammatory responses, which can be overactive in asthma and lead to tissue damage. Eosinophils also play a role in the body's defense against other large pathogens, such as bacteria and fungi, through phagocytosis.
Moreover, they contain antihistamines that counteract the activities of histamines released in allergic reactions. Nevertheless, when eosinophils become overactive, they can contribute to allergic reactions and asthma through the release of major basic protein and other inflammatory mediators.