Which statement about cytokines is NOT true?

Which statement about cytokines is NOT true?

• A. They function by signaling through receptors on cell surfaces
• B. They activate immune cells and can induce fever
• C. They are produced primarily in the liver
• D. They can increase vascular permeability

Answer: (C)

Cytokines are signaling proteins produced by immune and other cells to coordinate the immune response. They exert their effects by binding to specific receptors on target cells, which then changes gene expression and cell behavior. That signaling through cell-surface receptors is why this family of molecules can strongly influence how immune cells respond to infection or injury. They activate immune cells and can induce fever because certain cytokines, such as IL-1 and TNF-α, act as pyrogens and stimulate the hypothalamus to raise body temperature, while also promoting the activation and coordination of immune cell functions. The statement about being produced primarily in the liver isn't accurate. The liver isn't the main source of cytokines themselves; rather, cytokines are produced by various cells, especially macrophages, dendritic cells, T cells, and other immune cells. The liver responds to cytokines by producing acute-phase proteins like C-reactive protein and fibrinogen, which amplify inflammation and help limit infection. They can increase vascular permeability as part of the inflammatory response, allowing immune cells and molecules to access affected tissues more readily. This effect helps frontline defense but can also contribute to swelling and tissue changes during inflammation. So the false statement is that cytokines are produced primarily in the liver.

Cytokines are signaling proteins produced by immune and other cells to coordinate the immune response. They exert their effects by binding to specific receptors on target cells, which then changes gene expression and cell behavior. That signaling through cell-surface receptors is why this family of molecules can strongly influence how immune cells respond to infection or injury.

They activate immune cells and can induce fever because certain cytokines, such as IL-1 and TNF-α, act as pyrogens and stimulate the hypothalamus to raise body temperature, while also promoting the activation and coordination of immune cell functions.

The statement about being produced primarily in the liver isn't accurate. The liver isn't the main source of cytokines themselves; rather, cytokines are produced by various cells, especially macrophages, dendritic cells, T cells, and other immune cells. The liver responds to cytokines by producing acute-phase proteins like C-reactive protein and fibrinogen, which amplify inflammation and help limit infection.

They can increase vascular permeability as part of the inflammatory response, allowing immune cells and molecules to access affected tissues more readily. This effect helps frontline defense but can also contribute to swelling and tissue changes during inflammation.

So the false statement is that cytokines are produced primarily in the liver.