Describe the difference between active and passive immunity?
Active immunity occurs when the body fights off antigen through humoral and cellular immune response and creates memory for that antigen. This can occur naturally, from contracting the illness and fighting it off or it can occur artificially, from receiving an immunization and in response, the body creates memory cells from an adaptive immune response against the injected virus.
Passive immunity occurs when the body is not exposed to antigen but instead is administered antibodies from another body or source. Examples of this include naturally, through the passing on of antibodies from mother to child through breast milk and placenta and, artificially, by being injected immunoglobulins or antibodies for illnesses. For passive immunity, protection ceases when the antibodies degrade, whereas active immunity stores a memory.