Dorothy FarrarMacrophage
A macrophage is a large, mobile cell . It belongs to the immune system .
Definition
Macrophages are scavenger cells (phagocytes) that belong to the group of white blood cells ( leukocytes ). The term macrophage comes from ancient Greek and means “big” (macro) and “eat” (phage). The scavenger cells form an important part of the human immune system and eliminate harmful microorganisms.
The large mononuclear cells arise from monocytes, which arise in the bone marrow . Their half-life is about 72 hours. The monocytes are able to survive as tissue macrophages for a few weeks or even months. If an infection occurs in the body , chemotaxis ensure that it drives to the site of origin of the disease. In the tissue, they then differentiate into macrophages with the help of antigens and cytokines.
Anatomy
The monocytes, which are formed in the stem cells of the bone marrow, act as the progenitor cells of the macrophages. Only when a disease occurs do the monocytes differentiate into different types of macrophages. If it is a macropage that is bound to a specific location, the cell’s morphology conforms to the adjacent tissue.
From an anatomical point of view, a macrophage resembles a unicellular organism that has a nucleus . The maximum size of the phagocyte varies between 25 to 50 µm. By reaching this size, the macrophage is able to capture bacteria that grow to 5 µm in size. The harmful bacterium is then enclosed in a phagosome (phagocytes) of the phagocyte.
A large number of lysosomes are located in the cytoplasm of a macrophage. Lytic enzymes are found in these small organelles, with which phagotized germs can be killed. This process activates the macrophage. In addition, cytokines are secreted, which serve to control the inflammatory response.
The macrophages are also capable of causing lysozyme to be synthesized. The lysozyme, in turn, has the ability to break down glycosidic bonds. If bacteria come into direct contact with the lysozyme, this causes their cell walls to dissolve.
Function
The main activity of macrophages is phagocytosis of harmful microorganisms and foreign bodies. Even degenerated cells belonging to the organism are combated. The same applies to degenerated body cells that have already died. This process is part of the non-specific defense. The harmful germs are trapped by the scavenger cells in their phagosomes, where they divide them into individual sections from which damage can no longer emanate.
Another important function of macrophages is the presentation of antigens. These are mostly residues of peptides. The protein components are, so to speak, presented to the outside by the macrophage via a complicated mechanism. The presented fragments can be recognized by special T helper cells. This is followed by a synthesis of specific antibodies.
The macrophages can also produce cytokines together with other components of the immune system. These include B lymphocytes, T lymphocytes, fibroblasts and natural killer cells. Cytokines are proteins and peptides that the defense system uses to control the immune response. With the help of cytokines, the body’s defense system activates or deactivates the level of immune responses.
The spleen contains special macrophages that are CD-1969 positive. In the case of a virus infection , they increase the number of virus particles so that the immune response can take place more quickly. To prevent negative effects from escaping viruses, additional scavenger cells surround the CD-1969-positive macrophages. If a virus actually escapes, it is immediately destroyed by the other macrophages.
However, there are also macrophages in the immune system that do not phagocytose. Instead, they are important for repairing muscle fibers .
Diseases
- Hemophagocytosis Syndrome
Complaints caused by malfunctioning macrophages only rarely occur. In most cases, other diseases are the origin of health problems. The symptoms can thus be classified as a natural reaction of the macrophages.
One of the rare diseases of the scavenger cells is hemophagocytosis syndrome (HLH). This leads to excessive activation of the scavenger cells, which not only results in the phagocytosis of red blood cells, which can be disposed of, but also of healthy body cells.
Hemophagocytosis syndrome usually takes a severe course. It is often innate. The disease can also be acquired over the course of life. Possible triggers are infectious diseases or certain drugs.
Another disease of the macrophages is Gaucher syndrome. This is a metabolic disease in which the intermediate product glucocerebroside is not broken down properly. Instead, the substance accumulates in the lysosomes of the scavenger cells, causing them to swell. If these Gaucher cells accumulate in the bone marrow, spleen, nervous system or liver , life-threatening organ failure can result.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.