(How) can CD8 cytotoxic T cells kill bacteria in the gut?

[jaclnbateau]

So I know T cells do not recognize a full antigen, but require a peptide presented on MHC. I know some intracellular bacteria shed proteins that a somatic cell may process and present on MHC I for a CD8 T cell to recognize.

 

My question is: how - or whether - extracellular gut bacteria can initiate a T cell response? That is, they naturally only have the full antigen on their capsule/wall, they do not present a peptide-MHC complex... So how can these T cells recognize these gut bacteria? (and possibly destruct them...)

 

 

Any input would be highly valued!

 

 

P.s. I know there are alternative mechanisms involving antibodies, macrophages, NKs, etc... to combat bacteria, but I am specifically interested in finding out whether and if so how the CD8 T cell response is regulated

[Function]

I wasn't taught this specific matter, but I'd say they just live happily ever after in your guts ... CD3/CD8-positive T-lymphocytes usually reside in the bloodstream, so they'd already have to pass through all the mucosal layers of the intestines and blood vessels to reach the microbiota in the intestines. Nonetheless, there's such thing as intraepithelial lymphocytes (IEL), which can immediatly act upon recognition of an antigen, but they don't reach the lumen of the intestines, I guess ...

 

There's also no need for your CD3/CD8-positive T-lympho's to eradicate your microbiome.

 

As such.

 

You ask us to leave other immune cells out of the picture, but they contribute to it substantially, and cannot be neglected nonetheless.

Edited April 7, 2017 by Function