5.5 The components of innate immunity

pathogen-associated molecular patterns

molecules that are found in pathogens but are not found in a host, allowing them to be recognised as foreign

phagocytosis

bulk movement of solid material into cells where the cell engulfs a particle to form a phagosome

phagocytes

types of white blood cell, including neutrophils and macrophages, that can engulf and destroy foreign material

macrophages

phagocytic cells found in tissues, which eliminate and engulf pathogens by phagocytosis and clear dead cells and debris

Neutrophils

abundant immune cells that are usually the first to the site of an infection, engulfing and destroying pathogens

Dendritic cells

professional antigen-presenting cells, engulfing pathogens and presenting their antigens to T cells to activate the adaptive immune response

Eosinophils

a type of white blood cell that contain granules, enabling them to kill larger parasitic agents

natural killer cells

special white blood cells involved in the innate immune response that kill virus-infected cells

granzymes

active protease enzymes present in granules that form part of the immune defences of NK cells and cytotoxic T cells

perforin

a protein, released by some immune cells, that produces a pore in the membrane of cells undergoing an immune attack

mast cells

release histamines that increase vascular permeability and cytokines that attract other immune cells to help destroy the pathogen

histamine

a substance involved in inflammation and allergic reactions that causes blood vessels to dilate and become more permeable to immune cells