interferon
Meaning of interferon: Named for interfering with viruses, these proteins warn neighboring cells before infection reaches them and cause the flu-like feeling of being ill.
Definition of interferon
Interferon names a family of signaling proteins released by cells that detect a virus or certain other threats. They lock onto receptors on neighboring cells and switch on hundreds of genes that make those cells hostile to viral replication, buying time before the infection spreads. Interferons also recruit and tune the wider immune reaction, and some slow the division of cells.
What are the different types?
| Type | Main members | What it mainly does |
|---|---|---|
| Type I | Interferon alpha and interferon beta | Released by almost any infected cell; puts surrounding cells into an antiviral state |
| Type II | Interferon gamma | Released by T cells and natural killer cells; activates macrophages and steers the immune response |
| Type III | Interferon lambda | Acts on the lining surfaces of the airway and gut, limiting viruses with less whole body inflammation |
All three work through the same broad idea and differ in which cells carry the receptor for them. That receptor distribution is what makes type I effects felt across the whole body while type III effects stay largely at the surfaces where viruses arrive.
How is interferon used as a treatment?
Manufactured versions have been given for decades. Interferon alfa, usually in a long acting form, treats chronic hepatitis B and was once the backbone of hepatitis C treatment, a role now largely taken by direct acting antiviral tablets that work better and are far easier to tolerate. It is also used in hairy cell leukemia and certain other cancers, where competition from newer immune treatments has narrowed its place. Interferon beta is a long established treatment for relapsing multiple sclerosis, and interferon gamma is used in a rare inherited defect of the cells that kill bacteria.
Why does treatment feel like the flu?
Because the aching, fever, chills and exhaustion of a viral illness are not caused by the virus directly. They are the effect of interferons and related signals on the brain and muscles. Giving interferon as a drug reproduces that state deliberately, most sharply in the hours after each dose and often easing over the first weeks of a course. Longer treatment can also lower blood counts, disturb thyroid function and affect mood, which is why people receiving it are monitored rather than simply reviewed at the end.
Also known as
Used in a sentence
Interferon therapy was considered as part of the treatment plan for the patient's chronic viral infection.
Good to know
Interferon can slow the growth of certain cancer cells in addition to its role against viral infection, which is why its therapeutic uses extend beyond antiviral treatment.