Definition:
A vaccine is a drug consisting of all or part of an infectious agent. The infectious agent may be bacteria, viruses, parasites.
Administered orally or by injection, it will stimulate the immune reactions of the body so that it will then defend against the microbe itself.
Immunity
- Either the whole microbe. In this case, the microbe is killed and unable to infect the body. What are its components that will cause the immune defense reaction.
- Either the whole microbe that was just reduced by special treatment and is now therefore not virulent. The body immediately antibodies against the microbe. The problem is that it can become virulent among those whose defenses are weakened.
- Either a component of the microbe (fragment of the capsule of the virus for example), or an enzyme closely related to the capsule, which has been identified as an antigen stimulating strong immune responses.
How does it happen?
- Whether the vaccine stimulates the cells of cellular immunity, which keep the memory and will attack more strongly the microbe during a subsequent contact. This is the case for example of BCG.
- Whether the vaccine stimulates receptors on B cells that produce antibodies. In a subsequent contact, production of antibodies is more rapid and intense, preventing disease development.
Tags: bacteria, immunity, microbe, parasite, vaccine, virus
