How does a vaccine produce immunity to a disease
Answers
Vaccines are like a training course for the immune system. They prepare the body to fight disease without exposing it to disease symptoms.
When foreign invaders such as bacteria or viruses enter the body, immune cells called lymphocytes respond by producing antibodies, which are protein molecules. These antibodies fight the invader known as an antigen and protect against further infection.
Vaccines are made of dead or weakened antigens. They can't cause an infection, but the immune system still sees them as an enemy and produces antibodies in response. After the threat has passed, many of the antibodies will break down, but immune cells called memory cells remain in the body.
When the body encounters that antigen again, the memory cells produce antibodies fast and strike down the invader before it's too late.
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Vaccine is actually the dead cells of a particular disease causing organisms. when it is injected to our body, our body suddenly sends antibodies to kill the cells. But the disease causing cells are dead. So they store the antibodies created by our body. when a real live disease causing cell enters our body then our body can fight against it actively as we have already a stock of antibodies and does not require more time to make thus preventing you from any diseases. hence the main objective is preventing diseases.