Which activity of neutrophils is inhibited by an LFA-1 antagonist, leading to increased infection risk?

Neutrophils play a crucial role in the immune response, particularly in their ability to reach sites of infection and inflammation. LFA-1 (Lymphocyte Function-associated Antigen 1) is an integrin expressed on neutrophils and is essential for various processes during an immune response.

The correct answer highlights the role of LFA-1 in mediating adhesion to endothelial cells in the blood vessels. This adhesion is a critical step that allows neutrophils to move out of the bloodstream and into tissues where they can perform functions like phagocytosis and combating infections. If an LFA-1 antagonist is present, it blocks this adhesion process, preventing neutrophils from effectively binding to the endothelium. Consequently, this inhibition leads to impaired traversal through the capillary wall, limiting the neutrophils' ability to migrate to the site of infection.

While the activities of phagocytosis, diapedesis, and migration are all essential for the neutrophil's role in the immune response, the inhibition of LFA-1 specifically impacts the adhesion of neutrophils to the endothelium, making it difficult for them to exit the circulation. This ultimately increases the risk of infections, as neutrophils are unable