HIV is affecting many people today. Society is trying to protect itself from being infected by the virus. It is known that the result of the development of the disease caused by HIV is fatal. From childhood, people are taught simple protection rules that help reduce the chance of contracting a virus. In the article, we will find out the detailed structure of the virus (HIV), how it attacks and interacts with the cells of the human body.
What is human immunodeficiency virus
HIV (human immunodeficiency virus) provokes a slow development of infection in a he althy body. When the virus enters the bloodstream, it begins to gradually destroy he althy cells of the immune system. During the life of the virus, its amount in the body increases, and the number of lymphocytes is steadily declining. From the onset of infection to death, doctors distinguish 5 stages that an organism infected with a virus goes through. The last stage is AIDSacquired immunodeficiency).
You can become infected with the virus through direct contact with an infected person. This usually occurs when interacting with mucous secretions or by damaging the skin. The following body fluids are dangerous:
- blood;
- semen;
- vaginal discharge;
- mother's breast milk.
When there is contact with infected material, the virus enters the body and hides for a while (incubation period). After that, it begins to act actively, and the first symptoms of infection appear.
This virus belongs to the retroviral family, a subclass of lentiviruses. The name of the subclass comes from the Latin word lente - "slow", which is directly related to the behavior of the pathogen. Once in the human body, it develops slowly, but the characteristics and structure of the virus (HIV) are such that in each body it behaves differently and multiplies at different rates.
Virus under the microscope
Upon closer inspection, the pathogen looks like a sphere, along the edges of which there are spikes. The size of the virus reaches 150 nanometers, which is larger than many other infectious agents. The outer layer of the sphere is responsible for the contact of the virus with the cells of the body. It consists of proteins and vertical growths.
In appearance, the spikes resemble mushrooms - they have a thin stem with a cap. Thanks to the growths, the virus can come into contact with other cells. Glycoproteins (GP120) are located on the top of the cap, and the stemconsists of transmembrane glycoproteins (GP41).
In the main (internal) part of the virus is the genome of 2 molecules, consisting of 9 genes. It is in them that the hereditary memory of the virus, accumulated during its existence, is laid. It contains information about the structure, the scheme of infection and the principle of reproduction of the virus. The gene itself is enclosed in a shell of matrix and capsid proteins (P17 and P24). You can look at the photo of the structure of the virus (HIV) throughout the article.
Scientists have identified 4 immunodeficiency viruses:
- HIV-1 is considered the most common type. The main territory of distribution is North and South America, Eurasia and Asia. This species is considered the main cause of HIV infection.
- HIV-2 is less common but is a direct relative of HIV-1. Causes human acquired immunodeficiency syndrome. The spread began in western Africa.
- HIV-3, HIV-4 is the rarest form of the virus.
The structure of the virus
Infecting the body and destroying immune cells are the main functions of the virus. The structure of HIV has the following:
- Nucleocapsid is the core of the virus. The composition includes 2 molecules and the enzymes revertase, protease and integrase. All these components are enclosed in a package of capsid proteins (P7, P9, P24), and on top are 2,000 molecules of P17 (matrix protein). They are located between the outer shell and the capsid.
- The membrane is the outer shell of the virus. It consists of a layer of phospholipids, membrane cells and glycoproteins (namelythey help to select the right molecules of the human body for the subsequent attack).
Virus proteins
The composition of the virus (HIV) includes the following proteins:
- Supercapsid. The structure of the virus (HIV) necessarily includes these components in its composition, since they help to perform anchor (with the help of a supercapsid, the virus attaches to the cell) and address (search for targets) functions. They belong to complex glycoproteins.
- Structural proteins help form the outer shell of the virus and its capsid.
- Non-structural proteins are responsible for the POL genes. Thanks to this type of protein, the reproductive functions of the virus occur.
- Capsid proteins form a niche for nucleic acid and also help create enzymes and are present in the virus genome.
What cells does HIV infect
When the virus enters the human blood, it attacks cells containing the CD4 gene (monocytes, macrophages, T-lymphocytes and all related cells). Due to the structure of the human immunodeficiency virus (namely, being part of a glycoprotein), it attacks cells with this gene. Locations affected by the virus:
- all lymphoid tissues;
- microglial cells (nervous system);
- cells of the intestinal epithelium.
The process of interaction between HIV and the target cell
The main defenders of the body are T-lymphocytes, they are sent to fight the virus. Lymphocytes contain the CD4 gene, to which the HIV virus responds. He joinsT-lymphocyte through the specified gene. As already mentioned, this process occurs due to the glycoproteins (GP120) located on the spikes of the virus. After that, the pathogen begins to actively penetrate into the lymphocyte - transmembrane proteins (GP41) help to do this.
The virus, which is inside the T-lymphocyte, enters a favorable environment for reproduction. Some time after active replication, the infectious agent becomes crowded inside the shell, and it bursts. This process is constantly repeated and more and more cells of the immune system die.
When taking blood for analysis, a he althy patient is determined by CD4 in the norm from 4 to 12 units. And in a person with HIV infection, their number decreases and ranges from 0 to 3 units.
Due to its structure, the HIV virus, getting into a he althy body, freezes for a certain time. He needs a period for adaptation - basically this period lasts about 7 days. After that, the stronger virus begins to act.
Due to the location of the virus inside the cells, it successfully hides from any drugs, and the immune system stops responding to it properly.
The stages of HIV development
The special structure of the HIV virus suggests its gradual development in the body. An increase in its number allows you to produce active attacks on the body. There are several stages of HIV development (for each person they proceed differently, depending on the state of the body at the time of infection):
- Incubation periodtakes from 2 weeks to six months. The duration depends on the number of viruses that have entered the body. If a small number hit, then they will need more time to increase in numbers. The stage proceeds without symptoms, but the person is already considered a carrier of the virus.
- Acute infection. At the second stage, the number of viruses grows, and the number of T-lymphocytes begins to decline. The first symptoms of the disease appear: lymph nodes increase, the temperature rises or a rash appears.
- The latent stage is the longest stage in time, it takes about 6-7 years. There are practically no external manifestations of the disease. The process takes place inside the body, viruses are actively engaged in the destruction of T-lymphocytes. If you take auxiliary, supportive drugs, the calm period can be extended up to 10 years.
- Stage of secondary diseases. This period begins after the destruction of most of the immune system. Any catarrhal disease proceeds with serious complications and the appearance of additional ailments.
- AIDS. At the last stage, the entire immune system is destroyed in the patient's body. Such patients stay in the hospital under round-the-clock supervision. Unable to fight, the body begins to completely exhaust itself, the organs stop working properly, tears and purulent wounds appear on the skin. Treatment can only alleviate the patient's condition and delay the inevitable outcome.
In order not to become infected with the virus, you must follow the rules of personal safety and remember that the pathogen can get intothe human body through contact with body fluids.
Knowledge of the structure of the virus (HIV) helps scientists fight this disease and restrain its development. Describe the symptoms that arose after a possible infection to the doctor - this will help to choose the necessary treatment.
