Presentation of CMV immediate-early antigen to cytolytic T lymphocytes is selectively prevented by viral genes expressed in the early phase

The regulation of antigen processing and presentation to MHC class
I-restricted cytolytic T lymphocytes was studied in cells infected
with murine cytomegalovirus. Recognition by cytolytic T lymphocytes
of the phosphoprotein pp89, the immunodominant viral antigen
expressed in the immediate-early phase of infection, was
selectively prevented during the subsequent expression of viral
early genes. The surface expression of MHC class I glycoproteins
and their capacity to present externally added pp89-derived
antigenic peptides were not affected. Because recognition of
several other antigens occurred during the early phase, a general
failure in processing and presentation was excluded. Since neither
rate of synthesis, amount, stability, nor nuclear transport of pp89
was modified, the failure in recognition indicates a selective
interference with pp89 antigen processing and presentation.