Which part of the immune response is primarily affected by the chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis?

The correct answer is 'Adaptive immune response'

Key Points

• Adaptive immune response:
  • The adaptive immune response is characterized by its ability to remember specific pathogens, allowing for a more efficient and rapid response upon subsequent exposures.
  • Chronic activation of the hypothalamic-pituitary-adrenal (HPA) axis results in prolonged secretion of glucocorticoids, which can suppress the activity of immune cells such as T cells and B cells that are crucial for the adaptive immune response.
  • This suppression can lead to a reduced ability to fight off infections and an increased susceptibility to diseases.

Additional Information

• Innate immune response:
  • The innate immune response is the body's first line of defense and includes barriers such as the skin, and immune cells like macrophages and natural killer cells.
  • While the HPA axis can affect the innate immune response, the primary impact is more significant on the adaptive immune response, making this option less accurate.
• Non-specific immune response:
  • The non-specific immune response refers to mechanisms that respond to pathogens in a generic way, including components of the innate immune system.
  • Although chronic HPA axis activation can affect non-specific immune responses, the more profound and lasting impact is on the adaptive immune system.
  • Bacterial immunity only:
    • This option is incorrect because the HPA axis affects the entire immune system, not just responses specific to bacterial pathogens.
    • The adaptive immune response includes immunity against a wide range of pathogens, including viruses, fungi, and parasites, not just bacteria.