A flow of how vaccines work?

Immune system and Antigen expand "arms race", the stronger immune systems nor the better a flow of vaccine is how to work of? the new Beijing News know weekly a macrophage is extended its fake enough to two capsules may be swallowed up by the pathogen of particles.

China and the Arab doctors have long known that patients with smallpox scab off ground into powder, blowing into the health of people in order to prevent smallpox in the nasal cavity. 1796 year United Kingdom doctor Edward proved by inoculating Cow Pox preventable smallpox. In the 1930s, scientists use chicken embryo culture viruses replace the animal organs to produce vaccines, to the end of World War II, mankind has animal cells can be used to train. After the introduction of modern technology, many classic historical cases will gradually displacing Immunology known space. The rise of Immunology, greatly increasing the level of human health, increased life expectancy.

Then, immune what happened? body, viruses, bacteria, antibodies, cell is a kind of an immune function of the war? vaccine end geometry?

1 three lines of Defense to the immune system

"Every organization has a security system.

" Yellow Jianshi banner for interpretation of the body's immune system," whoever enters it security will have to look at the documentation, look at you is the unit that is acquaintance will let you in, if not done then stopped you. "The human body is an immune system, such as one barrier preventing the invasion of exotic pathogens. The so-called foreign matter on the Immunology were called "Antigen."

The first is the physical barrier to bacteria cannot enter the skin, small to cover the digestive, respiratory, reproductive tract and other area of 400 square meters of mucosa.

The first line of defense in blocking a lot of viruses, bacteria and parasites pathogens.

The second is called the "inn

ate immune system," defence. When we accidentally broken fingers, the skin immediately hung up, this is the second line of defense in the work. Many people have heard of macrophages, this is the second line of defence in General. And all the blood, they derived from bone marrow. It has consumed the invading pathogen microorganisms, and other particles. When the macrophage Phagocytic bacteria, will free up some chemical substances, these chemicals can increase flow to the flow of blood around the wound, the lead organization red, sometimes can cause shrinkage of the vascular wall cells, leading to partial swelling.

If the enemy is gradually increasing, macrophages irrepressible, also called the "keepers" to produce the proteins called cytokines to induction is wound around the capillaries in the walk in other macrophages and immune cells until they win the microbial world.

In this process, the human body will have a very strong inflammatory response, such as fever and fester. This is why people when leukocyte fever rises.

When the natural first and second lines of Defense are not able to resist the live virus attacks, humans have the third line of Defense — acquired immune system.

In this line of defence, foreign body accept the antigenic stimulation, resulting in immune responses. Vaccination, enter the immune cells, Antisera and other preparations are acquired immune system.

"The role of vaccines is tantamount to notify security.

" Yellow Jianshi said," informed that today dress in red to the don't let him come in a yellow dress tomorrow, don't let him in. Also you can mobilize a lot of ' security ', until the virus destroyed. ”

Until the 18th century, 90 years ago, human beings do not know the existence of immune defence.

At that time, the ceiling is a serious epidemic, doctor Jean na discovery, milking women workers are often infected with a known as cow pox diseases, their hand will be similar to the smallpox virus-induced pustule, but they are not infected with smallpox. Jenner from cowpox disease Department extract some secretions, they managed to prevent the spread of a smallpox.

2 active prevention, selective memory

Scientists study the Pasteur in France of rabies found that bacteria may spread in the animal's nervous system.

He used to cultivate rabbit brain, after the rabies virus attenuated experiment, ultimate success made the rabies vaccine. This became the Immunology of a classical case in history.

Subsequently, immunology, recognizing the presence of blood in a class of a specific protein, called "antibodies", which induces these antibodies produced substances are called "Antigen."

Cow Pox Virus and eggs in incubation of a flow of viruses are antigens. The limitations of this line of defence is that each antibody can only be combined with a specific antigen, and two main roles, T cells and B cells relevant.

"Saliva, tears of sterilization is not selective, so long as to the micro-organisms, viruses, and will play the role of Defense.

" Lean camel said. "B-cells are able to identify antigens, and combined to produce antibodies and cell division of debris to other cells, allowing them to keep in mind that this results in a memory. " B-cells to recognize through the other immune cells, such as Dendritic Cell processing transfer from foreign bodies from, and produces antibodies with role, although the life of B cells are limited, but the immune system to produce antibodies against specific foreign body has the ability of the duration is not a memory.

Because the cells of this kind of "memory", the organism will be manufactured antibodies, tag virus for macrophages to devour and degradation.

B cells induced humoral immunity is, it will be after human infections in the blood and bone marrow in the body for many years, once again the same type of Antigen, b-cell will immediately start replication, manufacturing antibody rose. And b-cells, T cells can do it came, where "T cells" force lethal hardcoreThat can directly destroy infected cells,

Recently there have been reports that some local ex with a flow of blood where a flow of critically ill patients.

This is equivalent to inject directly to human antibodies. "Rehabilitation of the body have been produced antibodies, similar to the principle of the antiserum. " Lean camel said," been a snake, detoxification antiserum to injection. Serological reaction "is a traditional immunological methods that belong to a passive immune, but modern science into vaccines are constructed automatically active immunization.

Because the selectively, human antibodies have immune memory, produce an antibody is a time to remember antigens and may even remember my whole life, such as smallpox and measles, too, won't have time.

However, the other to seasonal influenza, this memory is not too large.

Because influenza virus variants too quickly, once the antibody recognizes the virus fragment mutate, such recognition would fail. Due to the influenza virus has a large number of "variations", scientists are very difficult to predict what the flu season is what kind of flu virus outbreak. More importantly, the influenza virus mutation is very fast, often let people by surprise. "It's like security previously identified with glasses is the enemy, the glasses are uniquely identify, once enemy next time without glasses and do not know. " Lean camel said.

"It is important that the vaccine virus to healing virus closer and better vaccines will be more effective, and that is why we have to re-evaluate the seasonal influenza viruses.

" Karnes said," If H1N1 virus has undergone significant variation, it now uses a vaccine efficacy may be weakened. ”

Now, in Norway, Ukraine, China, Japan, Mexico, the United States and Brazi

l, have discovered the H1N1 virus in a variation, known as the D222G mutation, scientists now does not determine this variant of the risk. However, Karnes, based on existing data, mutation of the virus appears to not be smaller than the popular H1N1 virus death rate higher, or more infectious. These variations, not only in patients with severe symptoms, also found in some minor symptoms was found, and the H1N1 virus deaths.

3, the stronger the better immunity is not

"The virus is designed to take your health to reproduce themselves, not to kill you.

" Lean camel said. Invasion of the body of the virus, although you can do a lot of bad things, but their ultimate purpose is to survive in the host. Influenza virus infection base is large, in humans, animals in spreading fast, but relatively speaking it's death rate is very low, it is because of this, it has become a pandemic influenza. By contrast, the death rate is very high but it is hard to spread the virus. "Such as Ebola virus in Africa, died from infection to very quickly, the virus has not spread, the host has already died. ”

Normal seasonal influenza, there is no impact on people's basic needs.

Even the 1918 flu, Spain is not particularly high mortality rates. However, once the animals of influenza viruses and virus-to-human transmission of fused together, mortality can be high. This is the current scientists worry about avian influenza. Avian influenza mortality is very high, but because the people who have not yet spread variant of the virus in adults, so the transmission capacity is still very weak.

Some viruses, and the human form "long-term coexistence" situation.

The most typical is lip herpes virus that can cause blisters, when the lips long blister self-healing, when the body due to various reasons, haemoglobin is where arises, that is some people "chill out" his blistering. This virus can follow a person for life.

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"Virus infection, what is the purpose is to allow ourselves to live better, an ideal State is viral and host in harmony, it does not kill you, you also can't cure it, to maximize the benefits from each other.

" From biological evolutionary perspective, the virus is the most" longevity ".

"The evolution of different viruses, can adopt different strategies (such as restructuring and missing) to escape the host's immune defense.

Influenza virus generally use gene rearrangement, the use of recombinant hepatitis b virus. "Professor of life sciences, Fudan University, Zhong Yang said. The relationship between human and viruses have their advantages. The smallpox virus is the only human declared the eradication of virus that is about to step in the footsteps of the poliovirus, Herpes Zoster, herpes virus can lip and humans coexist, but there are many viruses during the long process of biological evolution have been integrated in our genome, become part of us.

Therefore, if you want to talk about the human immune system, but also to understand a reason: not immunity higher the better.

Most of the human body is composed of micro-organisms, microorganism was mixed, and human coexistence, to know when the immune system at work, the battlefield is the human body, immune system too strong, you may be normal cells are also seen as the enemy.

"SARS is immunity reaction excessive put people to death.

" Yellow Jianshi said:" the immune system can fight the virus, can deal with your own. "" Thus, many health food advertising in the so-called ' improve immunity ', is untenable, at most can say resistance high is a good thing. ”

New thematic interviews/reporter Kim Yu

This special appreciated:

LisaCairns (who immunization group representative office, immunity project team), yellow Jianshi (Peking Union Medical College Professor of epidemiology), Zhong-Yang (Fudan University, Professor,

school of life), Shu yuelong (China Centre for disease prevention and control of viral diseases prevention and control The Deputy Director, Director of the national influenza centre), thin camel (popular science writer)