Vaccination is the process of exposing an individual to an antigen to stimulate an immune response and produce antibodies to that antigen. Vaccines employ the benefits of "priming" the immune system for exposure to a pathogen.
Many vaccines are "attenuated" or disabled forms of a pathogen.
These attenuated pathogens are recognized by lymphocytes resulting in clonal expansion and production of plasma cells and memory cells.
The memory cells lie dormant until later exposure to the virulent pathogen, at which point they become activated.
This secondary response will involve contact with more immunospecific memory cells initially, which results in a faster, more robust immune response.
