Question

A) Define vaccine.
B) What is Antigen and Antibody?

Answer 1

First vaccine developed by Edward jenner i.e cowpox vaccine. It is a biological substance designed to protect humans from infections caused by bacteria and viruses. A vaccine contains at least one antigen from the bacteria or virus in order to get a response.

Complete answer:
To answer this question you must know all about the immune system. Immune system is a 24-hour machine which protects us from pathogens. It has the ability to recognize, neutralize or destroy and eliminate harmful foreign substances including microorganisms.

(A) Vaccine is the ‘antigen’ containing biological substance designed to provide protection against various unwelcome foreign antigen and it is also called immunizations because they take advantage of our natural immune system ability to prevent infection or illness.

(B) Antigens are substances which stimulate an immune response. Each antigen has distinct surface features or epitopes ,resulting in specific responses. If any foreign substance enters the body and starts a process that causes disease then the body usually produces a substance called antibodies to fight with the antigen.
Antibodies (immunoglobulins ) are Y shaped proteins which are produced by B cells of the immune system. if an foreign antigen enters our body. antigen contains a paratope which recognizes a specific epitope of an antigen.
So overall we can say the vaccine is the substance which produces antibodies inside our body to protect us from foreign antigen.

Note: Taking a vaccine is called vaccination and it is the safest way to eradicate various types of diseases from society. To produce response to a particular pathogen the antigen and antibody bind to each other like lock bind to key and this binding helps to eliminate foreign antigen by neutralization and the vaccine stimulates antibody memory response without causing illness or sickness.