Neutrophils vs Macrophages
Neutrophils and macrophages are leukaryotes which belong to innate immune system, and are considered as the main initial defenders against pathogens. These specialized cells can squeeze through the small holes of blood vessels, a process called diapedesis, which ultimately enables them to travel to the areas of infection easily. Normally when a tissue is damaged, an inflammatory reaction takes place at that site. This is due to the chemical substances released by bacteria into the surrounding tissue and blood. These chemicals eventually trigger the attraction of neutrophils and macrophages. The process of migration towards these chemical substances is called chemotoxis, hence considered as the very first significant reaction of defence action against pathogens. Both types of cells can phagocytise pathogens in the infected area.
What is Neutrophil?
Neutrophils are terminally differentiated cells that contain a plethora of proteolytic enzymes and reactive oxygen species that cause local tissue damages when released extracellular matrix. It takes about 14 days to develop a neutrophil in bone marrow. After that, they start circulating in the bloodstream for 6 to 14 hours. Nearly 50% of the circulating neutrophils adhere to the vascular endothelium. These neutrophils can survive for another 48 hours, unlike the rest of the neutrophil cells that are not attached to vascular endothelium.
What is Macrophage?
Macrophages are considered as the oldest mediators of the innate system and are derived from monocytes, which are produced in bone marrows. Once monocytes are released and migrated to various tissues, they differentiate into macrophages. These macrophages are called tissue macrophages. Tissue macrophages can live for months to years until they are needed and destroyed upon performing their defensive function. Tissue macrophages are considered as the main effectors in the defense system against intracellular pathogens.
What is the difference between Neutrophil and Macrophage?
• Macrophages can live longer than neutrophils.
• Since macrophages are larger than neutrophils, they can phagocyte greater number of invader pathogens than neutrophils.
• After infection, neutrophils dominate the infected site early while macrophages dominate infected sites at later stages (1 to 2 days after infection).
• Unlike the neutrophil, macrophage can present the antigenic fragments to the T lymphocytes in the context of MHC (Major Histocompatibility Complex) class II molecules after engulfing the bacterial cells.
• Unlike the macrophage, neutrophil has multilobed nucleus. The nucleus of macrophage is big and round shaped.