Immune evasion proteins gpUS2 and gpUS11 of human cytomegalovirus incompletely protect infected cells from CD8 T cell recognition.
Human cytomegalovirus (HCMV) encodes four glycoproteins, termed gpUS2, gpUS3, gpUS6 and gpUS11 that interfere with MHC class I biosynthesis and antigen presentation. Despite gpUS2-11 expression, however, HCMV infection is efficiently controlled by cytolytic CD8 T lymphocytes (CTL). To address the role of gpUS2 and gpUS11 in antigen presentation during viral infection, HCMV mutants were generated that expressed either gpUS2 or gpUS11 alone without coexpression of the three other proteins. Fibroblasts infected with these viruses showed reduced HLA-A2 and HLA-B7 surface expression. Surprisingly, however, CTL directed against the tegument protein pp65 and the regulatory IE1 protein still recognized and lysed mutant virus infected fibroblasts. Yet, suppression of IE1 derived peptide presentation by gpUS2 or gpUS11 was far more pronounced. The results show that gpUS2 and gpUS11 alone only incompletely protect HCMV infected fibroblasts from CTL recognition and underline the importance of studying infected cells to elucidate HCMV immune evasion.
Besold
K
K
Institute for Virology, University Medical Center, Johannes Gutenberg-University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz, Germany.
Wills
M
M
Plachter
B
B
D017951:Antigen Presentation / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000235:genetics / Q000276:immunology* / Q000502:physiology; D003586:Cytomegalovirus Infections / Q000276:immunology* / Q000821:virology; D015789:HLA-A2 Antigen / Q000276:immunology; D015793:HLA-B7 Antigen / Q000276:immunology; D006801:Humans; D017874:Immediate-Early Proteins / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D016296:Mutagenesis; D010750:Phosphoproteins / Q000276:immunology; D016601:RNA-Binding Proteins / Q000235:genetics / Q000276:immunology*; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D014763:Viral Matrix Proteins / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology*; D014779:Virus Replication
D015789:HLA-A2 Antigen; D015793:HLA-B7 Antigen; C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; C074546:US11 protein, herpesvirus; C118670:US2 protein, Varicellovirus; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C065418:cytomegalovirus matrix protein 65kDa; D007371:Interferon-gamma