Acquired Immunity

Acquired immunity

It is pathogen-specific, i.e., when a germ enters into our body antibodies are produced against it while it is called the primary response. In the future, if the same germ enters the body. The antibodies recognize them and fight against it, which is called the secondary response. There are 2 types of lymphocytes B and T lymphocytes. The B lymphocytes produce antibody and the T lymphocytes help them to produce it.

1 Structure of antibody

Each antibody molecule has 4 peptide chains- 2 small light chins and 2 longer heavy chains (H2N2). There are 4 types of antibodies, namely IgG, IgA, IgM and IgE.

Figure: Structure of the antibody

2 Humoral immunity

The immunity that we get through the production of antibodies by the lymphocytes is called humoral immunity.

3 Cell-mediated immunity

Our cells have the ability to identify self from non-self. So during organ transplantation along with blood group matching, tissue matching also should be done. Because our cell will identify the transplant as a foreign body and kills it by producing antibodies. If tissue matching is done, cells cannot identify it as a foreign body. A patient who has undergone organ transplantation has to take immune supplements throughout his life.

4 Active immunity

When a pathogen enters our body, our body’s lymphocyte produces an antibody against it. This type of immunity is called active immunity.
It is a time taking process.
The principle of immunization is based on the memory of our immune system.
A vaccine is an inactivation germ, a dead germ, or the poison produced by it. When it enters our body (antigen) our body produces antibodies against it. In the future, if the same germ enters the immune system recognizes it, and affects the germ.

5 Passive immunity

When readymade antibodies are directly given to protect the body against the pathogen (antigen) is called passive immunity.
Colostrum secreted by the mother during the initial days of lactation has readymade antibodies IgA to protect the baby.
The foetus also receives some antibodies from the mother through the placenta. Another example of passive immunity is an antivenom for snake bite. In the case of snakebite, the injection which is given to the patient contains antibodies against the venom of the snake.