Over the years, scientists have made quite a few animals glow green (when illuminated by blue/near UV light). See an earlier post for glowing fish. Marmosets, pigs, mice etc all have been made to glow. And now cats have joined the list, thanks to the work of Wongsrikeao and coworkers. See here for a picture of a glowing cat. Handy if you can’t find Molly at night.

But there is a serious purpose to this: fighting HIV, the virus that causes AIDS. Also, fighting the related feline immunodeficiency virus (FIV), which causes a disease related to AIDS in cats.

Both cats and ourselves have complex sets of immune systems for fighting things like viruses. One part of these systems is a last-ditch system that acts when the virus is already in one of our cells.

This brings me to another animal: the rhesus macaque. Rhesus macaques are known to be immune to HIV. The picture above is of a young rhesus macaque monkey – cute and immune to HIV. It appears that this may be due to a protein molecule in this last-ditch immune system.

This protein is called TRIM5α (it is funny name but I won’t bother explaining it as it a bit complicated). Both us and rhesus macques have this protein. But our version of the TRIM5α protein and the version in rhesus macaque monkeys are different, unfortunately only the rhesus-macaque version works against HIV.

The experiments with the glowing cats are part of an effort to see if we can fight HIV by importing the rhesus macaque version of the protein into the cells of another species, in this case cats. The research reported is just one step towards importing the rhesus macaque’s immunity to HIV to us but it is encouraging, both for us and for our furry friends.

How the rhesus-macque TRIM5α works is, I think, remarkable, and it has been captured in a movie. The movie is from a paper of Andersen and coworkers.

The movie shows the inside of a living cell, and the red thing is an actual HIV virus which is moving around inside the cell. The green things are basically droplets (each with maybe 100 molecules) of the TRIM5α protein. You can see them moving around too, and in the movie you can see the green TRIM5α droplet capturing the red HIV virus.