Which component of blood is responsible for fighting off pathogens?

White blood cells are the component of blood primarily responsible for fighting off pathogens, which include bacteria, viruses, fungi, and other harmful microorganisms. They play a crucial role in the immune system, employing various methods to identify and destroy these invaders. There are several types of white blood cells, each with specific functions, such as neutrophils that respond quickly to infections, lymphocytes that target specific pathogens, and monocytes that help to engulf large pathogens and dead or damaged cells.

In contrast, red blood cells are primarily involved in transporting oxygen from the lungs to the body's tissues and carbon dioxide from the tissues back to the lungs. Platelets are small cell fragments that are essential for blood clotting and wound healing, while plasma is the liquid component of blood that carries cells, nutrients, hormones, and waste products, but does not directly participate in pathogen defense. Together, these components work collaboratively, but it is the white blood cells that specifically target and combat pathogens, making them the key players in immune response.