poly AU
Meaning of poly AU: A synthetic RNA that imitates a virus, used to rouse the immune system rather than to attack anything directly.
Definition of poly AU
Poly AU is a laboratory made double stranded RNA, built by pairing a chain of adenine units with a chain of uracil units. Cells treat double stranded RNA as the signature of a virus, so the molecule sets off an alarm response and the release of interferon. It has been studied as an immune stimulant given alongside cancer treatment rather than as a treatment in itself.
Why does the body react to it?
Long double stranded RNA is not made by healthy human cells, but many viruses produce it while copying themselves. Sensors inside cells and on their surface watch for it, and one of them binds it directly. Poly AU is built to trip that sensor. The cell then responds as it would to an infection: it releases interferon and other alarm signals, increases the display of proteins on its surface so immune cells can inspect it, and draws natural killer cells and dendritic cells into the area. Nothing is actually infected, so the result is an alarm without a fire.
How does it compare with poly IC?
| Poly AU | Poly IC | |
|---|---|---|
| Strands | Polyadenylic acid paired with polyuridylic acid | Polyinosinic acid paired with polycytidylic acid |
| Survival in blood | Broken down quickly by enzymes | Also degraded, so stabilized versions were developed |
| Interferon released | Modest | Stronger |
Both belong to the same family of synthetic double stranded RNAs, and poly IC has been the more widely studied of the two.
What has it been studied for?
Interest has centered on using it as an adjuvant, meaning a substance added to provoke a stronger immune response rather than to kill anything itself. Studies have paired it with surgery or with vaccines, on the reasoning that a roused immune system would deal with cells left behind. Some early work in breast cancer reported a benefit, but the approach was never adopted into standard care and the compound remains investigational. Its cytotoxic effect, where one appears, comes from the immune cells it summons rather than from any direct poisoning of a target.
What limits it?
The enzymes that clear stray RNA from blood dismantle the molecule within minutes, so exposure is brief and hard to control. A general alarm across the whole body also brings fever, chills and aching, the familiar price of an interferon surge. Later research has largely shifted to more stable relatives and to small synthetic molecules that hit the same sensors with more predictable timing.
Also known as
Used in a sentence
The protocol combined a tumor vaccine with poly AU as an immune adjuvant.
Good to know
Poly AU works by rousing the immune system rather than by attacking cells directly, and it has remained an investigational compound rather than an established treatment.
Word origin
Where “poly AU” comes from
Poly comes from the Greek polys, meaning many, since the molecule is a long repeat of two units, adenylic acid and uridylic acid.