PATHOLOGY

Detailed explanation-1: -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-2: -The type of virus or bacteria to which you are first exposed is the version your immune system will tend to remember the best. So when you are exposed to a second or third type of the pathogen, your immune system will react as if it is still recognizing the first type.

Detailed explanation-3: -In secondary responses, on antigen rechallenge, memory B cells are activated and have at least two fates: they either differentiate into long-lived plasma cells or enter GCs to undergo rounds of population expansion, SHM and selection (Fig.

Detailed explanation-4: -Memory T and B lymphocytes have an essential role in the immunity against microbial pathogens but are also involved in autoimmunity and maternal-fetal tolerance. Furthermore, the evidence of immunological memory has been established for NK cells.

Detailed explanation-5: -In a secondary response to the same antigen, memory cells are rapidly activated. This process is quicker and more effective than the primary response.