Dear everyone,
Please help me to solve this question.
In theory, when virus infection, Antigen-presenting cells uptake them, and process them to be specific antigen, and present and activate naïve T cells to be effector cells. Here, I am wondering that, when a virus infects a host cells, it will develop, live inside of host cells. So it means that, probably, virus antigens will not be expressed on host cells surface, so my question is:
How CD8+T cells can recognize and kill virus infected cells when virus antigens are not expressed on the surface of host cells?
Thank you!
Hi Cuong,
When viral proteins are expressed in the cytosol of infected cells, these proteins are broken down by the proteasome and peptides loaded by TAP onto Class I MHC molecules, which are shuttled to the cell surface and can present the peptide antigen to CD8+ T cells. If viral antigens are not presented on the cell surface, I would not expect CD8+ T cells to kill infected cells. However if the infected cells are driven to down-regulate MHC expression, they may be recognized by NK cells and killed via the NK mediated pathway. See Heath R. et. al. Nature Reviews Immunology (2001) 1:126.
Hope this helps
Benjamin
it is possible that virus will kill infected cells after replication and lots of virus will be exposed. these exposed virus will be taken by Dendritic cells in blood and with process of cross presentation they present it to CD8 T cells through MHC1 molecules.