Which of the following immune cells are primarily involved in fighting off parasitic infections?

Eosinophils are specialized white blood cells that play a crucial role in the immune defense against parasitic infections. They contain granules filled with toxic proteins and enzymes that can damage and kill parasites, particularly helminths (worms), which are among the larger type of parasites. When the body detects a parasitic infection, eosinophils are recruited to the site of infection where they release these granules, leading to the elimination of the parasites.

In addition to their direct action against parasites, eosinophils also participate in the modulation of inflammatory responses and interact with other immune cells, contributing to a tailored response in parasitic infections. Their levels in the blood can increase significantly during such infections, providing a marked indication of ongoing immune activity against parasites.

Natural killer cells, while effective in targeting virally infected cells and certain tumor cells, are not primarily involved in fighting off parasitic infections. Neutrophils generally respond to bacterial infections and early inflammatory responses rather than specifically targeting parasites. Lymphocytes, which include T cells and B cells, play important roles in immune responses, such as the adaptive immune response, but the specific targeted action against parasites is primarily the domain of eosinophils.