The immune system is our body guard, which protects it from foreign biological material. Recognizing foreign substances, it liquidates them, while “remembering” the answer to, if necessary, use it when dealing with a similar virus. In the absence of the immune system we would have been easy prey for viruses, fungi, bacteria, and helminths. Slight draft would affect most difficult infectious disease deaths. And so it happens in people with immune deficiency, immune functions are weak. And it does not matter it is innate or acquired (eg HIV infection) – the effect is the same.
One of the main problems of immunity, as already mentioned – recognition of “native” and “alien” biological substance. With the native biological substance meets the immune system in the womb, the knowledge of the “Alien” gets by inheritance, as well as many other genetic quality. In this case it is called hereditary or innate immunity. Still, with the “alien” biological substance immunity often have to learn by direct contact with him. This will be called acquired immunity, it is not as resistant as congenital and inherited is not transmitted. Acquired immunity is divided into two types, the active and passive. In order to acquire active immunity, a person must have had the disease or a vaccination (vaccination).
The principle of the vaccine is introduced into the body that the individual agents or part of a pathogen, it can be proteins or polysaccharides. Can also be used whole dead or weak pathogenic substances or live vaccines, obtained by genetic engineering. Thus, the body itself produces antibodies are necessary to allow fast enough to overcome the infection. Active immunity can be operated from a year or more, for example, vaccination against influenza is valid 1 – 2 years, measles – for decades, from chicken pox during the whole life.
Passive immunity occurs when the introduction of antibodies into the body ready to another person or animal. Methods of acquisition of passive immunity can be both a natural way, on the basis of the embryo receives maternal antibodies through the placenta. And artificial, by injection of antibodies acquired from human serum, had undergone the disease, or re-produced by the method same genetic engineering.
If vaccination can cause side effects, the most common ones – it is an allergic reaction. Allergy is manifested on the skin in the form of redness at the injection site, and possible itching, peeling skin. It may also be more serious reaction such as fever, shivering, rapid decrease in blood pressure. Out of fear of side effects, many refuse vaccination. But now a vaccine, which includes micro-organisms themselves, changed the drugs, which contain components of microorganisms. This is a milder version of the vaccine, it almost does not cause adverse reactions, as well as the development does not cause disease in immunocompromised individuals. This type of vaccine – a completely new stage in the development of vaccines.
Natural Immunity 