Video Transcript
How do memory T-helper cells
provide protection against a second infection of the same virus? (A) They increase the body’s first
line of defense to the virus. (B) They rapidly stimulate
cell-mediated and humoral immune responses. (C) They raise the temperature of
the body through cytokine release. (D) They stimulate white blood cell
synthesis in the bone marrow. (E) They shut down the primary
immune response through cytokine release.
Lymphocytes, like T cells and B
cells, recognize antigens on the surface of pathogens in order to mount an immune
response to clear the infection. Antigen-presenting cells can
phagocytose pathogens and present its antigen on the cell surface. This antigen-presenting cell can
then interact with a T-helper cell that recognizes this antigen. This activates the T-helper cell,
which can go on to activate B cells in the humoral immune response and cytotoxic T
cells in the cell-mediated immune response. In addition, memory T-helper cells
are produced with specific receptors for the same antigen.
When a second infection with the
same pathogen occurs, another antigen-presenting cell can phagocytose it to present
its antigen. The memory T-helper cell carries
the receptor specific for this antigen, so it can respond quickly and become
activated. This activated memory T-helper cell
can then go on to rapidly activate B cells in the humoral immune response and T
cells in the cell-mediated immune response.
Therefore, the correct answer
choice is (B). They rapidly stimulate
cell-mediated and humoral immune responses.
