Phagocytes

Macrophages (; abbreviated Mφ, MΦ or MP) are a type of white blood cell of the innate immune system that engulf and digest pathogens, such as cancer cells, microbes, cellular debris and foreign substances, which do not have proteins that are specific to healthy body cells on their surface. This self-protection method can be contrasted with that employed by Natural Killer cells. This process of engulfment and digestion is called phagocytosis; it acts to defend the host against infection and injury.

alt=|thumb|323x323px|Overview of phagocytosis thumb|300px|Phagocytosis versus exocytosis Phagocytosis () is the process by which a cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs phagocytosis is called a phagocyte. thumb|The engulfing of a pathogen by a phagocyte In a multicellular organism's immune system, phagocytosis is a major mechanism used to remove pathogens and cell debris. The ingested material is then digested in the phagosome. Bacteria, dead tissue ce

Neutrophils are a type of phagocytic white blood cell and part of innate immunity. More specifically, they form the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. Their functions vary in different animals. In humans they participate in processes such as sterile inflammation, tissue repair, and cancer, and exhibit coordinated collective behavior. They are also known as neutrocytes, heterophils or polymorphonuclear leukocytes.

thumb|Scanning electron microscope|Scanning electron micrograph of a neutrophil phagocytosing anthrax bacilli (orange)|alt= Long rod-shaped bacteria, one of which has been partially engulfed by a larger blob-shaped white blood cell. The shape of the cell is distorted by undigested bacterium inside it.

type of immune cell

immune response that does not involve antibodies

Any mechanism of immune avoidance that directly affects the host immune system, e.g. blocking any stage in host MHC class I and II presentation. The host is defined as the larger of the organisms involved in a symbiotic interaction.

macrophage found in the pulmonary alveolus