ANATOMY

Detailed explanation-1: -However, some persist after the antigen has been eliminated. These cells are known as memory cells and form the basis of immunological memory, which ensures a more rapid and effective response on a second encounter with a pathogen and thereby provides lasting protective immunity.

Detailed explanation-2: -In the primary response to infection, antibodies are secreted first from plasma cells. Upon re-exposure to the same pathogen, memory cells differentiate into antibody-secreting plasma cells that output a greater amount of antibody for a longer period of time.

Detailed explanation-3: -During the secondary immune response, the immune system can eliminate the antigen, which has been encountered by the individual during the primary invasion, more rapidly and efficiently. Both T and B memory cells contribute to the secondary response.

Detailed explanation-4: -Active immunity results when an immune response to a pathogen produces memory cells. As long as the memory cells survive, the pathogen will be unable to cause a serious infection in the body. Some memory cells last for a lifetime and confer permanent immunity. Active immunity can also result from immunization.

Detailed explanation-5: -Secondary response and memory The memory B cells produced during the primary immune response are specific to the antigen involved during the first exposure. In a secondary response, the memory B cells specific to the antigen or similar antigens will respond.