The viral proteins expressed on infected cells are those produced
endogenously. Virtually all nucleated cells express class I molecules
and have the proteasome pathway for the production of peptide
fragments of 8-13 amino acids which will bind to the class I
molecules. These are then expressed on the surface of the cell for
interaction with the T cell receptor of CD8+ T cells. When antigen is
expressed on class I molecules the convention is to call the cell a
target cell rather than an APC.
On Fri, 5 Nov 1999 11:20:07 +0100, "Morten Lindow" <lindow at mdb.ku.dk>
wrote:
>I have got a question about the activation of naive T-cells by viral
>antigens.
>>According to my textbook (Janeway-Travers) activation of CD8+ T-cells
>require recognition of MHC class I loaded with viral antigen and
>costimulation through CD28 by B7.1 or B7.2 on an APC. All this takes place
>in lymphoid tissue.
>>The question is: What happens if a virus doesn't infect APCs? Say it is
>specific for epithelial cells. How does viral peptides then end up on
>class I molecules on APCs? I figure that APCs could phagocytise free viral
>particles, but wouldn't that result in presentation on class II MHCs?
>>Is there a flaw in my understanding? Any ideas and comments would be very
>welcome.
>>>Regards,
>>Morten Lindow
>Copenhagen, Denmark
>>
