Question

How do antigens and antibodies of the blood develop?

Answer 1

The antigens are the molecules that trigger the formation of the antibodies when introduced into the body. On the other hand, the antibodies are the immunoglobulins. They are produced as a response to antigenic stimulation.

Complete answer:
Antigens and antibodies are both Humoral immunity. The B-lymphocytes produce an army of proteins in response to the pathogens. When the pathogens enter the blood, the B-lymphocyte cells get activated and differentiate into the plasma cells. These cells secrete a large number of antibodies to fight the pathogens. The B-lymphocytes that remain undifferentiated are stored as memory.
The word antigen is made up of two words, Anti meaning antibody and Gen meaning generating. Therefore, the antigens stimulate the production of antibodies in response to the pathogen or infection. Antigens are the large proteins or polysaccharide molecules that are found on the cell walls of bacteria and coats of viruses. However, all antigens are not parts of microorganisms and can be found in other structures as well.
On the other hand, the antibodies are the immunoglobulin molecules that are formed as a result of the stimulation caused by antigens. The molecule of the antibody has light and heavy chains. There are antigen-binding sites present that binds the antigen.

Note:
The antigens and antibodies are both the types of humoral immunity, which is a type of acquired immunity. The acquired immunity is the immunity that is gained after birth. It is pathogen-specific immunity. When the body encounters the pathogens, it initiates a primary response. This primary response helps in secondary encounters.