IMMUNITY AND IMMUNISATION (VACCINATION)

IMMUNITY is the in build capacity of the body to resist almost all types of pathogens or toxins which tend to damage the tissues and organs of the body. This power of the body is provided by phagocytes (Body cells that eat up foreign particles), acid and enzyme secretion in the digestive tract, resistance of the skin against invading organisms and presence of certain chemicals in the blood. There are three line of defence in our body which one after another get involved in protecting the body if invaded by any microorganism. The first line of defence by provide by psycho-chemical barrier consisting of skin with fatty acids, low pH, hairy nasal passage with sticky mucus, mucus membrane which contain lysozyme and anti-microbial chemicals. The second line of defence is provided by phagocytic cells of our body i.e. WBC (White blood cells) and the third line of defence is provided by immunoglobulins or antibodies which are produced by the body cells in response to the presence of antigens in our blood. Antigens are all the foreign organic molecules that cause diseases in our body. The ability to produce specific antibody against antigens is limited to only vertebrates which is a great evolutionary advancement is our body.  There are two systems of immunity in our body i.e. Humoral or antibody mediated immunity system and Cell mediated or Cellular immunity system. Bone marrow plays the the major role in both types of immunity by producing lymphocytes. There are two types of lymphocytes in our body i.e. T-lymphocytes and B-lymphocytes. T-lymphocytes are responsible Cell mediated immunity and B-lymphocytes are responsible for Humoral immunity.

Immunity of two types: Inborn or innate immunity and Acquired or adaptive immunity. Inborn immunity is inherited by the organisms from their parents and protects throughout the life. For example human being have inborn immunity against a disease called distemper (a fatal disease of dog). Acquired immunity or adaptive immunity is acquired in lifetime. Acquired immunity is of two types again: Active (Natural) and Passive (Artificial).  In active immunity, organisms own cells produce antibody against antigens but in passive immunity, antibody is produced outside the body i.e. in some other organism and is injected in infected person. Passive immunity provides immediate relief while active immunity takes time to produce antibodies in the body. A mother provide passive immunity to her baby through her milk. A mother transfers antibodies produced in her body to infants. Bottle-fed infants do not get this benefit. So, it suggested to feed new born babies with mother’s milk as their immunity system does not work in the initial stage but it starts working after few weeks.  The mammary glands of a female undergo differentiation during pregnancy and start producing milk towards the end of pregnancy by the process called lactation. The milk produced during the initial few days of lactation is called COLOSTRUM which contains several antibodies absolutely essential to develop resistance for the new born babies. Breast-feeding is always suggested during the initial growth of infants for bringing up a healthy baby.

Immunity in a person can be developed during his/her lifetime in three ways:

By Vaccination: It is a technique to develop immunity without infection. Weakened or dead pathogens are injected into a person whom to be immunised. The pathogens given a vaccine do not cause disease but are sufficient to stimulate the formation of antibodies in the injected body. These remain in the body for lifetime and protect it from attacks of the same pathogens in future.
By Antitoxins: Antibodies that neutralize toxins (Poisons) produced inside the body or introduced from outside are called antitoxins. Some antitoxins are prepared in the body but some are prepared from outside the body like antitoxins for snake venoms are prepared snake venom by injecting it in a horse.
Immunity through diseases: Some disease like mumps, measles, small pox produce a lifelong immunity in the body. So, these diseases never appear again.
 

To be healthy, we should be exposed to the environment where we live. An isolated lifestyle may be very harmful for a person as he/she is in more risk be suffered from diseases if exposed to his/her own environment. A baby should be allowed to play in an open environment to get immunised naturally. In the initial stage, they may suffer little bit but it will develop their immunity for lifetime. An isolated living is not at all healthy living. In modern days, most of the children suffer from various diseases even if little bit exposed to their environment. Its time, we should reconsider the lifestyle of our children. We are destroying their self-immune power in the name hygienic lifestyle. An isolated living always does not mean hygienic lifestyle. We must differentiate these two definitions properly i.e. hygienic lifestyle and isolated lifestyle.

“MOTHER’s MILK IS BEST MILK”