Mechanism of Action
The exact mechanism of action in which imiquimod and its analogs activate the immune system is not yet known. Nevertheless, it is known that imiquimod activates immune cells through the toll-like receptor 7 (TLR7), commonly involved in pathogen recognition. Cells activated by imiquimod via TLR-7 secrete cytokines (primarily interferon-α (INF-α), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α)). There is evidence that imiquimod, when applied to skin, can lead to the activation of Langerhans cells, which subsequently migrate to local lymph nodes to activate the adaptive immune system. Other cell types activated by imiquimod include natural killer cells, macrophages and B-lymphocytes.
New research has shown that imiquimod has anti-proliferative effects in vitro that are independent of immune system activation or function. However, those effects do not apply to skin cancer cells.
Imiquimod exerts its effect by increasing levels of the opioid growth factor receptor (OGFr). Blocking OGFr function with siRNA technology resulted in loss of any antiproliferative effect of imiquimod.
Read more about this topic: Imiquimod
Famous quotes containing the words mechanism of, mechanism and/or action:
“A mechanism of some kind stands between us and almost every act of our lives.”
—Sarah Patton Boyle, U.S. civil rights activist and author. The Desegregated Heart, part 3, ch. 2 (1962)
“I’ve never known a Philadelphian who wasn’t a downright “character;” possibly a defense mechanism resulting from the dullness of their native habitat.”
—Anita Loos (1888–1981)
“Economic depression can not be cured by legislative action or executive pronouncement.”
—Herbert Hoover (1874–1964)