How Your Immune System Works

Human immune system nicely responses to the entering of foreign molecules (called antigens) into the body - it localizes antigens, then neutralizes them to destroy them. When immune system works normally, it is able to protect us from a great range of contagious diseases including our own pathologic cells which are formed in the body.

However, when immune system begins to work incorrectly or stops its work entirely, this may result in such severe diseases as AIDS or cancer. Normal immune reaction may occur naturally when agents of viral infection enter the body or may be activated artificially with the help of various vaccines.

Most vaccines contain dead or very weak microorganisms which cause development of particular disease (pathogens) . These microorganisms just activate immune reaction and do not cause the disease itself. Immunity acquired after vaccination is as strong as natural immunity which appears after body fight with viral infection. However, vaccination not causes in man usual disease symptoms in order to produce normal defensive reaction of immune system. Vaccination is performed gradually against viruses causing such diseases as measles, parotitis, roseola, influenza, poliomyelitis, hepatitis, and also some bacterial infections.

The effectiveness of body immune system work reduces slowly, and as a result with aging immunity becomes weak. It was found that most of cancers which appear in older people result from “aging” of immune system.