How can a cytokine still act after it’s gone

Here is yet another new wrinkle in how drugs act.

Type I interferons are  very well studied cytokines, important in the defense against viruses.  There are 16 of them, and in response to infection, they induce the expression of over 300 antiviral genes (ISGs — Interferon Stimulated Genes).

Type I interferon is gone from the plasma after intramuscular injection in a few hours, yet its effects last days to weeks.  Well maybe the proteins it induces hang around a long time.

Not so says Proc. Natl. Acad. Sci. vol. 117 pp. 17510 – 17512 ’20.  It hangs around inside the cell in little vesicles formed from pinching off part of the cell membrane containing type I interferon bound to its receptor.  These are called endosomes.  The authors call this siloing.  The silos persist for days and can actually be seen if you use fluorescently labeled type I interferon.  The endosomes with type I interferon inside persist for days.

I’m sure people are actively studying other cytokines of which there are many, many — e.g. there are more than 50 interleukins that we know about.

Post a comment or leave a trackback: Trackback URL.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: