How does the immunity of human body work when an infection attacks the organism? essay sample

The immune system is an incredibly complex set of cells that coordinate with each other and perform different functions. Some of them define dangerous agents such as viruses and respond to the other cells that destroy the virus. There are several types of white bodies in our blood such as macrophages and lymphocytes, which cope with germs. Macrophages kill viruses as soon as they define them. But if the infected person has a weakened immune system, these cells cannot cope with the assault of infection which spreads quickly around the organism. At this stage, lymphocytes intrude into the process.

T and B lymphocytes are powerful cells, which perform different roles. B lymphocytes attach to the virus and produce antibodies – a specific protein that makes the virus visible to the remaining cells. They also can stop the virus from replicating. T lymphocytes act differently. Some of them give a signal to the others that there are strange cells to be destroyed while the remaining T lymphocytes kill the virus immediately or produce more antibodies. After the infection has been defeated, T and B cells “memorize” characteristics of the virus to prevent recontamination. This physiological phenomenon is called an acquired immunity.

The natural ability of the body to remember its invaders is indeed a wonderful mechanism of defense.  It allows scientists to create vaccines. Childhood immunization is an essential stage in building an acquired immunity to such diseases as measles, mumps, and rubella. When treated at the young age, these diseases pose no danger to children, but at the age of adolescence and later they may drag severe complications.