Individuals or Mice with Defects in the Biochemical Pathways Needed

Individuals or mice with defects in the biochemical pathways needed for loading peptides onto MHC molecules show greatly increased susceptibility to virus infections. Experiments examining the MHC molecules present on the surface of host cells in these individuals would show:

A) Normal numbers of MHC molecules expressed on host cells, but no peptides bound to them.
B) Very low levels of total MHC proteins expressed on the cell surface.
C) Normal numbers of MHC proteins on the surface but all of them bound to self-peptides not pathogen peptides.
D) Very high levels of total MHC proteins expressed on the cell surface.
E) Only virus-infected cells expressing high levels of MHC proteins on the cell surface.