ANATOMY

Detailed explanation-1: -When these memory cells meet their specific antigen again, they rapidly proliferate and differentiate into plasma cells. These plasma cells then respond by producing abundant quantities of antibody to clear the antigen.

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: -Correct answer: Explanation: An acquired immune response to a secondary infection by a pathogen results in presentation of antigen to residual memory helper T-cells, memory T-cells, and memory B-cells. Upon recognizing the antigen, memory T-cells can become cytotoxic T-cells and target the infected region.

Detailed explanation-4: -During the secondary immune response, these cells are involved in the reaction against foreign antigens, including pathogens, and take part in autoimmune diseases, but also are crucial to immunological tolerance and vaccine therapy.

Detailed explanation-5: -Once the immune system recognizes a pathogen as “non-self, ” it uses cellular and chemical defenses to attack it. After an encounter with a new pathogen, the adaptive immune system often “remembers” the pathogen, allowing for a faster response if the pathogen ever attacks again.