What is Immunity?
Immunity is a condition of being able to resist a particular disease especially through preventing development of pathogenic microorganism or by counteracting the effects of its products. It is the capability of the body to resist harmful microorganisms or viruses from entering it. The healthy immune process is capable to recognize invading viruses, bacteria and also produce antibodies to destroy or disable them. It is the ability of the body to restrict dangerous microorganisms or viruses from entering it.
Types of Immunity:
There are four types of immune system which are explained in the below:
1. Innate (Natural) Immunity:
It is the natural resistance components such as intact skin, salivary enzymes, and neutrophils, natural killer cells, which provide an initial response against infection that is present in an individual at birth prior to exposure to a pathogen or antigen.
2. Adaptive (Acquired) Immune System:
3. Active Immunity:
It refers to the method of exposing the body to an antigen for generating an adaptive immune response. The response takes days/ weeks to develop but may be long- lasting. For example recovery from Hepatitis-A virus gives a natural active immune response that usually leading lifelong protection. In a similar manner, administration of two doses of Hepatitis-A vaccine generates an acquired active immune response which leading to long lasting defense.
4. Passive Immunity:
It refers to the method of imparting IgG antibodies to keep safe against infection. It gives immediate, but short- lived protection such as several weeks to 3 or 4 months at most. It is occurs during pregnancy. The transfer of maternal tetanus antibody (mainly IgG) across the placenta provides passive immune to newborn baby for several weeks/ months until such antibody is degraded and lost.