Antibodies work INSIDE virus-infected cells

You already know that we use antibodies in several ways to combat infection in our immune system.  They bind to pathogens, they activate complement, you know the drill. Well, here's another bullet point to add to your antibody slide: we've found a new intracellular role for the antibody.

Researchers have recently shown that antibodies can attach to a virus, which then enters a host cell where a molecule called TRIM21 quickly binds at Fc on the IgG antibodies.  By ubiquitin ligase activity, TRIM21 targets the virus's proteins for destruction by the proteasome.

Click here for an awesome animation that shows all this violent destruction in a simple, dramatic way. Your students will love this animation, because the proteasomes' rapid and total destruction of the virus is so amazing to watch.  And it's a good opportunity to emphasize the importance of the proteasome in the cell. 

Not only does this observation give us a new intracellular role for antibodies, it also highlights a new and important strategic link between innate immunity (TRIM21/proteasome action) and adaptive immunity (antibodies).

Want to know more?

Antibodies mediate intracellular immunity through tripartite motif-containing 21 (TRIM21)
Donna L. Mallery, et al.
Proceedings of the National Academy of Science November 16, 2010 vol. 107 no. 46 19985-19990
Published online before print November 2, 2010, doi: 10.1073/pnas.1014074107
[This is the original paper, available open access]

Read this shortened evaluation highlighting the key findings:
Koch D, Sawtell N: 2010. F1000.com/6381958

Come Inside
R. Grant
The Scientist Volume 25 Issue 3 Page 58 2011-03-01
[Quick and easy summary, including that awesome video]

By the way, I love those movies showing miniaturized submarines exploring the inside of the body . . . and this reminds me of the SyFy thriller Antibody with Lance Henriksen and Robin Givens.  Yes, it's a hokey movie, but I like the scenes showing the immune cells attacking the miniaturized sub.