Final answer:
Lectins, proteins expressed by endothelial cells near an infection site, specifically bind to oligosaccharides on the surface of target cells.
Step-by-step explanation:
The endothelial cells found closest to the site of an infection express proteins called lectins. Each lectin binds to a particular oligosaccharide that is presented on the surface of a target cell. Lectins are specific carbohydrate-binding proteins that play a crucial role in cell-cell recognition and adhesion. In the context of infections, the endothelial cells utilize lectins to bind to oligosaccharides on the surface of pathogens or infected cells, enabling the immune system to target and address the threat effectively.