Which specialized cells in the liver are responsible for removing pathogens from the bloodstream?

Kupffer cells are specialized macrophages located in the liver that play a crucial role in the immune response. Their main function is to phagocytize (consume and digest) pathogens, such as bacteria and debris in the bloodstream, thereby helping to cleanse the blood of harmful microorganisms. These cells line the hepatic sinusoids and are essential for maintaining the homeostasis of the liver while also playing a significant role in the body's defense against infection.

Hepatocytes, while critical for various liver functions such as metabolism and detoxification, do not specialize in removing pathogens from the bloodstream. Endothelial cells, which form the lining of blood vessels, have various functions in the vascular system but are not primarily involved in phagocytizing pathogens. Sinusoidal cells refer broadly to the specialized endothelial cells of the liver sinusoids, which facilitate the passage of blood and cells but also do not primarily perform the phagocytic actions characteristic of Kupffer cells. Therefore, the role of Kupffer cells as the main defenders against pathogens in the liver is what makes them the correct answer to this question.