MACROPHAGES

MACROPHAGES

Subject : Science & technology

Context : Researchers at Karolinska Institutet in Sweden describe how different kinds of immune cells, called macrophages, develop in the lungs and which of them may be behind severe lung diseases.

Concept :

• The structure of the lungs exposes them to viruses and bacteria from both the air and the blood.
• Macrophages among other things, protect the lungs from such attacks.
• But under certain conditions, lung macrophages can also contribute to severe lung diseases, such as chronic obstructive pulmonary disease (COPD) and COVID-19.

MACROPHAGES

• Macrophages are important cells of the immune system that are formed in response to an infection or accumulating damaged or dead cells.
• Macrophages are large, specialized cells that recognize, engulf and destroy target cells.
• Macrophages are formed through the differentiation of monocytes, one of the major groups of white blood cells of the immune system.
• When there is tissue damage or infection, the monocytes leave the bloodstream and enter the affected tissue or organ and undergo a series of changes to become macrophages.
• These macrophages can modify themselves to form different structures in order to fight various different microbes and invaders.
• The macrophages present in humans are around 21 micrometers in diameter. They can survive for months at a time. They are also involved in the development of non-specific or innate immunity.
• Each of the macrophages has specific protein markers on the cell surface. Some examples include CD14, CD11b, EMR1, MAC-1/MAC-3, Lysozyme M, and CD68. These markers can be identified using a technical process called flow-cytometry.
• Macrophages may have different names according to where they function in the body. For example, macrophages present in the brain are termed microglia and in the liver sinusoids, they are called Kupffer cells.