GED Science TestLife ScienceHard
A public health official is investigating an outbreak of a respiratory illness. They discover that the pathogen responsible is a virus that primarily targets and destroys helper T cells (CD4+ T cells). What long-term impact would this have on the immune system of an infected individual?
- AA significant weakening of the overall adaptive immune response.
- BOverstimulation of natural killer cells, leading to autoimmune reactions.
- CIncreased production of antibodies by B cells.
- DEnhanced cytotoxic T cell activity against infected cells.
Show answer & explanationAnswer & explanation
Correct answer: A. A significant weakening of the overall adaptive immune response.
Helper T cells are crucial orchestrators of the adaptive immune response, activating both B cells and cytotoxic T cells. Their destruction severely compromises the body's ability to fight off infections.
Why the other options are wrong
- B. While natural killer cells are part of immunity, helper T cells do not directly overstimulate them in a way that leads to autoimmune reactions upon their destruction; rather, the overall immune response is crippled.
- C. Helper T cells are required to fully activate B cells for antibody production, so their destruction would decrease, not increase, antibody production.
- D. Helper T cells also activate cytotoxic T cells; their destruction would impair, not enhance, this activity.
Helper T Cells (CD4+ T cells)
Lymphocytes that play a central role in the adaptive immune response by recognizing antigens and activating other immune cells.
- Crucial for activating B cells to produce antibodies.
- Essential for activating cytotoxic T cells to kill infected cells.
- Targeted by HIV, leading to AIDS.
Memory trick: Helper T cells are the generals, directing the immune army.