Macrophages - what kind of creatures are these? Or formations? What are they responsible for in our body? These, as well as a number of similar questions, will be answered in the framework of the article.
general information
Mononuclear phagocytes (or macrophages) are a group of long-living cells that are capable of phagocytosis. They have quite a few common functions that make them related to neutrophils. Macrophages are also active participants in complex inflammatory and immune reactions, where they act as secretory cells. How do they function? Macrophages, like neutrophils, leave the vascular bed by diapedesis and begin to go their own way - to circulate in the blood. But they are sent to the fabric. After this, the transformation of monocytes → macrophages occurs. And already at the place of arrival, they will perform their specific functions, which depend on the anatomical location. This applies to the liver, lungs, bone marrow and spleen. In them, they will be engaged in the removal of harmful particles and microorganisms from the blood. What can they “turn into" what? Kupffer and microglia cells, alveolar macrophages, macrophages of the spleen, lymph nodes, bone marrow - this is what they are transformed into.
Functional
The body’s macrophages have two main functions, which are performed by different types:
- Elimination of corpuscular antigens. This is what the so-called “professional” macrophages do.
- Absorption, processing and presentation of antigen for T cells. These tasks are already performed by the agro-industrial complex. Such a reduction is used due to the long name of the micro-level subjects - antigen-presenting cells.
When adult formations are formed from bone marrow promonocytes, especially a lot of them fall (and linger there) into lymphocytes. Macrophages perform their functional for a long time due to the fact that they are long-living cells that have well-developed mitochondria and a rough endoplasmic reticulum.
More about tasks
So, we know that, like neutrophils, macrophages leave the vascular bed and begin to perform certain functions. In general and in general, we have already considered this. Now let's take a more thorough look at what they are doing. So, they provide phagocytosis, produce enzymes, serum proteins, prostaglandins, oxygen radicals, cytokines, leukotrienes. In addition, macrophages are also involved in the secretion of neutral proteases, acid hydrolases, lysozyme, arginase, many enzyme inhibitors, nucleosides and cytokines. They also produce the active form of oxygen, arachidic acid. And macrophages are a factor in the activation of chemokines, platelets. It is impossible not to note their role in the destruction of tumor cells and the destruction of intracellular parasites. In the latter, their role is extremely important. Macrophages can merge into large cells, which under the influence of anti-inflammatory cyclones turn into granulomas. Such formations affect the amount of produced gamma interferon.
Immune role
But most attention should still be paid to the fight against protozoa, viruses and bacteria that exist inside the host cells. This is realized due to the presence of bactericidal mechanisms that macrophages possess. This leads to the fact that they are one of the most powerful tools of innate immunity. But that is not all. Together, they participate in the formation of the immune response in T and B lymphocytes. In addition, it is impossible not to note the role of macrophages in wound healing, elimination of cells that have already outlived their own, and with the formation of atherosclerotic plaques. They literally devour harmful elements in our body. This is even indicated by their name. So, translated into Russian, “macrophage” is a “big eater”. And it should be noted that these cells are really quite large.
What are the types of macrophages?
Since the formations we are considering are tissue phagocytes, their various “modifications” can be found in different parts of the body. If we consider absolutely everything, it will take a lot of time, therefore, attention will be paid to the most significant representatives, such as:
- Alveolar macrophages. They are located in the lungs and are engaged in the purification of the inhaled air from various harmful and polluting particles.
- Kupffer cells. They are located in the liver. Mainly involved in the destruction of old blood cells.
- Histocytes. They live in connective tissues, so it can be found throughout the body. But they are often called "fake" macrophages due to the fact that they are engaged in the formation of a framework for most body structures, and not directly the destruction of various harmful elements.
- Dendritic cells. They live in the epithelium and under the mucous membranes.
- Splenic macrophages. They are located in the sinusoidal vessels of this organ and are engaged in the capture and destruction of obsolete blood cells. No wonder the spleen is called the cemetery of dead red blood cells.
- Peritoneal macrophages. They live in the peritoneum.
- Macrophages of the lymph nodes. Where they live is obvious from the name.
Conclusion
Our body is composed. It is inhabited by many useful cells that make our life easier. Macrophages are no exception. Unfortunately, sometimes their experience is not enough for the immune system to work as necessary. And then a person gets sick. But an important advantage of our immune system is precisely that it can adapt.