How do white blood cells fight pathogens?

This type of immune response is universal to all pathogens and involves WBCs such as macrophages, dendritic cells, and monocytes. It also involves the release of neurotransmitters that activate other WBCs (cytokines and interleukins) and dilate blood vessels to allow more WBCs to arrive (histamine).

Since the acquired immune response is pathogen-specific, it takes longer than the innate immune response. The main players in the acquired immune response are B and T cells. B cells bind to the pathogen (antigen), become activated, and then, with the aid of Helper T cells, multiply to produce plasma antibodies to fight the pathogen and memory cells to retain the pathogen should it re-enter the body. Antigen-presenting cells such as macrophages and dendritic cells are necessary for the acquired immunity to function.

When intracellular pathogens are present, infected cells produce aberrant antigens that are quickly recognized by cytotoxic T lymphocytes, which bind to the infected cells and ultimately kill them.

White blood cells fight pathogens through various mechanisms, including phagocytosis, release of antimicrobial chemicals, and production of antibodies.