Question

An organism's immune system will rapidly respond to an antigen it has seen before. This secondary response activates a subset of lymphoid cells leading to a rise in antibody titer.
The subpopulation responsible for the initiation of this response is the

• A. Memory B-cell.
• B. Memory T-cell.
• C. NK-cell.
• D. Plasma cell.

Answer 1

Answer: (A)

Memory B-cell.

Organism's immune system respond to an antigen rapidly to an antigen that it has tackled before, this is called secondary response/immunity. These cells are memory B cells, that get activated/proliferate in response to helper T cells

So, the correct answer is 'Memory B-cell'